NASA Mission Set to Explore Pluto p. 30 THE ESSENTIAL MAGAZINE OF ASTRONOMY
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JUNE 2010
Hubble’s
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Summer Tour of Planetary Nebulae p. 70 A Binocular Comet at Dawn p. 60 Visit SkyandTelescope.com
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June 2010
86
VOL. 119, NO. 6 THI S M O N TH ’ S S K Y
40
Northern Hemisphere’s Sky By Fred Schaaf
43
June’s Sky at a Glance
45
Binocular Highlight
AL S O IN THI S I S S U E
By Gary Seronik
NASA / ESA / HUBBLE HERITAGE TEAM (STSCI/ AURA) / ESA/HUBBLE COLLABORATION
COVER STORY
Scientific Achievements Now that Hubble has been in space 20 years, a leading astrophysicist reflects on its most significant accomplishments. By Mario Livio
30 New Horizons:
Planetary Almanac
48
Sun, Moon, and Planets By Fred Schaaf
36 Turning 50
Spectrum
10 12
Letters 50 & 25 Years Ago By Leif J. Robinson
51 60
Exploring the Moon By Charles A. Wood
14
News Notes
Celestial Calendar
18
Cosmic Relief By David Grinspoon
By Alan MacRobert
65
Deep-Sky Wonders
58
New Product Showcase
68
Telescope Workshop
By Sue French
Halfway to a Historic Encounter An intrepid NASA spacecraft is speeding toward its June 2015 rendezvous with Pluto. By S. Alan Stern
8
By Robert Naeye
46 FE ATURE S
20 Hubble’s Greatest
JANE SANDERS
On the cover: This beautiful image of the star-forming region NGC 3603 was acquired by the Hubble Space Telescope.
By Gary Seronik
S &T TE S T R E P O R T
54
Atik’s 314L CCD Camera
76
Gallery
This exceptionally easy-to-use camera produces first-rate images. By Dennis di Cicco
86
Focal Point By Jim Bell
The entrepreneurial spirit of one amateur astronomer led to the creation of a legendary telescope company. By Dennis di Cicco
70 Flowers of the Night Sky
30 and
S&T: CASEY REED
Planetary nebulae come in a fantastic variety of sizes, colors, and shapes. By Ted Forte
SKY & TELESCOPE (ISSN 0037-6604) is published monthly by Sky & Telescope Media, LLC, 90 Sherman St., Cambridge, MA 02140-3264, USA. Phone: 800-253-0245 (customer service/subscriptions), 888-253-0230 (product orders), 617-864-7360 (all other calls). Fax: 617-864-6117. Website: SkyandTelescope.com. © 2010 Sky & Telescope Media, LLC. All rights reserved. Periodicals postage paid at Boston, Massachusetts, and at additional mailing offices. Canada Post Publications Mail sales agreement #40029823. Canadian return address: 2744 Edna St., Windsor, ON, Canada N8Y 1V2. Canadian GST Reg. #R128921855. POSTMASTER: Send address changes to Sky & Telescope, PO Box 171, Winterset, IA 50273. Printed in the USA.
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Robert Naeye Spectrum Founded in 1941 by Charles A. Federer, Jr. and Helen Spence Federer
Proposed NASA Budget Pros and Cons
The Essential Magazine of Astronomy EDITORIAL
Editor in Chief Robert Naeye Senior Editors Dennis di Cicco, Alan M. MacRobert Associate Editor Tony Flanders Imaging Editor Sean Walker Editorial Assistant Katherine L. Curtis Editors Emeritus Richard T. Fienberg, Leif J. Robinson Senior Contributing Editors J. Kelly Beatty, Roger W. Sinnott
After having weeks to digest the implications of the proposed new NASA budget, I still have mixed feelings about it. I’m troubled by the thought of canceling the Constellation program, which would send astronauts back to the Moon, especially after U.S. taxpayers have already shelled out $9 billion over the past five years. As critics point out, canceling Constellation outright postpones NASA’s return to the Moon indefinitely, and could lead to the erosion of an experienced workforce. I’m deeply concerned about the budget’s lack of Kennedy-esque clarity. It fails to provide any specific mission timetables for exciting destinations such as the Moon, a near-Earth asteroid, or Mars. Having a clearly stated objective could focus technology development and inspire the public. It places too much reliance on Russia and the private sector for ferrying U.S. astronauts to and from low-Earth orbit for the next decade. Parts of the plan come across as pie-in-thesky wishful thinking about technology development that may never materialize. On the flip side, if we’re sending people to the Moon or beyond, let’s do it right. Constellation is a well-conceived program, but it has always been underfunded and has thus fallen behind schedule. A committee chaired by former Lockheed Martin executive Norman Augustine issued a widely praised report last year saying that Constellation was putting NASA on an unsustainable trajectory. The committee outlined several options for the future of human spaceflight, including a call for more involvement from the private sector. Now that there’s an actual NASA budget proposal that follows some of these options, I’m disappointed that some pundits and politicians seem to be backing away. I’m excited about the budget’s plan to allocate more funding to the development of possible “game-changing” technologies, such as new heavy-lift rockets. If we stick with current chemical rockets, a round-trip manned mission to Mars would take 2 to 2½ years, which is probably a showstopper given the problems of space radiation, maintaining a self-contained life-support system, etc. I’m convinced that the only way I’ll ever see a human mission to Mars in my lifetime is if we can develop a new propulsion system that greatly reduces the timescale. This new NASA plan gives me at least a glimmer of hope that could happen. The proposed budget is now going through the Congressional meat grinder, and who knows what will emerge. I hope the administration and Congress can agree on an exciting long-term plan that builds upon the strengths of the proposed budget, and fi xes its shortcomings. Unfortunately, with a $12.7 trillion national debt and high unemployment, that might depend on money that the government simply isn’t willing to invest in human spaceflight right now. On an entirely different topic, my April Spectrum described why Chile is a great destination for astro-tourism. Despite the February 27th earthquake, it still is. I’m extremely pleased to report that my Chilean friends are safe, and all the major amateur and professional observatories I visited were undamaged.
Editor in Chief 8 June 2010 sky & telescope
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Contributing Editors Greg Bryant, Paul Deans, Thomas A. Dobbins, David W. Dunham, Alan Dyer, Sue French, Paul J. Heafner, Ken Hewitt-White, Johnny Horne, E. C. Krupp, Emily Lakdawalla, David H. Levy, Jonathan McDowell, Fred Schaaf, Govert Schilling, Ivan Semeniuk, Gary Seronik, William Sheehan, Mike Simmons, Charles A. Wood, Robert Zimmerman Contributing Photographers P. K. Chen, Akira Fujii, Robert Gendler, Babak Tafreshi ART & DESIGN
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Letters
David Grinspoon replies: This is an interesting idea, but the similarity seems like a coincidence to me. We must remember that there are many processes that can create holes in surfaces. Volcanic activity on a small moon such as Hyperion would not be expected, and we know that its surface is dirty water ice. The strange appearance of Hyperion is certainly a little mysterious, but most planetary scientists think that it probably has to do with the craterformation process in an object that has unusually low density, or the modification of craters in response to solar radiation on an object that is unusually dark and rotates very slowly.
On the Web O To listen to a Slacker Astronomy podcast on current developments in amateurdom, featuring S&T Editor in Chief Robert Naeye and Mike Simonsen of the AAVSO, visit http://trunc.it/68j02.
NICOLA CASTELLANO
I’m a geologist but have been interested in astronomy since I had my first scope when I was 12. I also collect minerals (more than 1,000 samples) and meteorites (70), and I’ve read Sky & Telescope for many years. So, when David Grinspoon wrote that Saturn’s moon Hyperion looks like a seasponge (October 2009, page 18), I remembered a sample in my mineral collection: a pumice (seen at right). My pumice is a glassy volcanic rock named rhyolite, in a particular form called “glass foam.” It’s formed by explosive liberation of gas contained in silica-rich lava, when the lava rises to Earth’s surface and is no longer under enough pressure to keep the gas dissolved. Is the similarity to Hyperion just a coincidence? Nicola Castellano Genoa, Italy
NASA / JPL / SPACE SCIENCE INSTITUTE
Rocky Comparison
One reader noticed the interesting similarities between Hyperion (left) and volcanic pumice rock.
Expanding Club Membership In Robert Naeye’s February issue Spectrum column, he addressed the lack of ethnic diversity in amateur astronomy and asked readers for their success stories. I am one of the founding members of the In Lak’ech Study Group here at Pleasant Valley State Prison in California. Our focus is the study of the ancient cultures of the Americas, a facet of which has been archaeoastronomy. This has fostered in our group a love for astronomy as a whole, both ancient and modern. Prison environments are renowned for being racially and ethnically charged, yet our study group includes members who are Native American, African American, Asian, White, etc., all of whom come
Write to Letters to the Editor, Sky & Telescope, 90 Sherman St., Cambridge, MA 02140-3264, or send e-mail to
[email protected]. Please limit your comments to 250 words.
Daily Sky-Event Diary: SkyandTelescope.com/ataglance
S&T Weekly Newsletter and AstroAlerts: SkyandTelescope.com/ newsletters
Combat Light Pollution: SkyandTelescope.com/darksky
Do-It-Yourself: SkyandTelescope.com/diy
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10 June 2010 sky & telescope
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together at our weekly stargazing sessions. Because of the light, we are limited to observing the brighter stars. But because everybody is looking up, no one cares about the color of the person next to them. We’re all just people sharing the wonders of the night sky above. If astronomy can foster such ethnic diversity in, of all places, a prison, then imagine what might be possible if we can get the rest of society looking up. Uguku Usdi Coalinga, California One of the clubs I belong to, the Warren Astronomical Society (in Michigan), is becoming successful at recruiting people outside the usual demographic. Way outside. We’re getting people of color, women, and younger people into their teens. We’ve done this the traditional way: through outreach events. But we’ve also established relationships with scouts and schools, including a high school with an astronomy program that includes building and operating a radio telescope. We have also offered everyone a free one-year membership. And the newest angle is meetup.com, where you can find people who are interested in a topic to get out and do something. Some of them pick our club events instead of basket weaving and so on. Meetup.com is not free to our club, but it has certainly been worthwhile for us. Now we have a new problem. We have two presentations a month, but the newbies can’t always follow our talks. Our tradi-
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Letters
tional members have gotten quite sophisticated. We need more entry-level talks! Astronomy clubs are always losing members to attrition, so to survive, they need to do everything than can to attract new members. Stephen Uitti Warren, Michigan
Lifelong Interest I felt compelled to write after reading so much about online social networks and the changing face of backyard astronomy. At 77 I’m still pursuing my five-decade interest in “low-level” amateur astronomy, enjoying my computer-driven Meade ETX125 scope in my 8-foot-diameter domed observatory in my backyard. I built the observatory since turning 70 and bought the molded polyethylene dome two years ago. I’m enjoying both very much, when the trees,
50 & 25 Years Ago
Leif J. Robinson
June 1960 Glimpsing Earth “The feasibility of surveying cloud patterns on a global scale has been demonstrated by the television system of Tiros I. This experimental weather-reconnaissance satellite was launched from Cape Canaveral on April 1st.” Blue Straggler Stars “A puzzling feature of many globular clusters is the presence in them of an appreciable number of fairly hot stars, in apparent defiance of the modern theory of stellar evolution. . . . “These are main-sequence stars, but they are located well above the turn-off point . . . where the densely populated, nearly vertical main sequence turns sharply to the right. These brighter blue stars cannot be explained away as foreground objects, because they share the motion of the cluster and therefore are a part of it.” How apparently young stars can exist in very old clusters perplexed astronomers for more than a half century. The leading theory today is that they are rejuvenated stars that resulted from stellar collisions or accretion long after star formation in the cluster was over.
12 June 2010 sky & telescope
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sky conditions, and my age permit. My first scope back in the 1950s was a 4-inch Criterion Newtonian reflector, followed in the 1960s by a 60-mm Goto refractor that I still have. My first log page is dated May 6, 1959, and I’m still keeping a log. I use a computer not for interacting with other amateurs, though I’m a member of the Cincinnati Observatory Center, but for Spaceweather, Jupiter’s moons, the Cassini mission, Mars rovers, SOHO sites, and Charles Wood’s LPOD site for the Moon. No matter how hard I may try, I just don’t lose my interest in astronomy and space travel. To all amateurs at whatever level, whether at the eyepiece or on a computer screen, keep at it! It will give you pleasure for a lifetime. Thomas P. Busemeyer Cincinnati, Ohio
June 1985 Venus Close-ups “‘Venera’ is the Russian word for Venus, but in the last decade it has come to mean more than that. It also represents an extensive series of Soviet spacecraft whose explorations have provided much of what we now know about that cloud-covered planet. Most recently, a pair of orbiters arrived there in October, 1983, equipped with synthetic-aperture radar to penetrate the clouds and probe the torrid surface below. . . . “Veneras 15 and 16 took eight months to map all of Venus above latitude 30° north, including the previously uncharted polar region.” Binocular Vision “Besides feeling more natural and relaxing, binocular vision enhances several areas of visual performance that are important for astronomical observing. These include increased contrast sensitivity, improved resolution, and the ability to detect fainter objects. . . . “Enhanced perceptions in the range of 40 percent are almost too good to be true, yet they are available by just using two eyes rather than one.”
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News Notes
Refining “Precision Cosmology”
NASA / WMAP SCIENCE TEAM
The world barely noticed, but the team running NASA’s Wilkinson Microwave Anisotropy Probe (WMAP) has released results from the satellite’s new “seven-year data set,” refining the most basic things we know about the cosmos as a whole. WMAP has been mapping the cosmic microwave background radiation that wallpapers the sky. The radiation dates from 380,000 years after the Big Bang, and its precise character tells much about conditions right back to the Big Bang itself. Since the previous “five-year” data set, two additional years of observations have further beat down the statistical noise in the cosmic background map (a piece of which is shown above). This allowed analysts to refine what it says. If the revisions didn’t make news, it’s because they show modern cosmology to be steady on course. Some high points: • The age of the universe is 13.75 plus or minus 0.11 billion years, compared to
13.73 ± 0.12 billion years before. • The Hubble constant, the rate at which the universe is expanding today, is 70.4 ± 1.4 km per second per megaparsec. (An independent study yields slightly different but consistent results, see page 23.) • Although those refinements are slight, combining them with the new WMAP values for many other parameters, as well as other improved evidence, tightens up the standard model of cosmology by 50% overall. • In particular, a key prediction of inflationary-universe theory is firmed up. Inflation traces the cause of large-scale cosmic structure — galaxies and galaxy clusters — back to random, microscopic quantum fluctuations within about 10 –32 second of the start of the Big Bang. The simplest versions of inflation predict that, during this first instant, the tiny quantum events did not produce equally strong irregularities on all size scales the way nature often
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works. Instead, the fluctuations should have been slightly stronger at larger scales. WMAP finds exactly that, written on today’s sky. (The so-called “scalar spectral index” is not exactly 1.0 but 0.96 ± 0.01.) This is a big deal for boosting confidence that the inflation process is indeed what made the Big Bang happen. • Space, as far away as we can see, is flat to a new degree of precision: 1.0023 ± 0.0055 of the critical flatness density. This is consistent with a value of exactly 1 (flat space) to an uncertainty of half a percent. • The “equation of state” of the dark energy filling space is –0.980 ± 0.053, consistent with a value of exactly –1 to an uncertainty of about 5%. This indicates that the dark energy, whatever it is, acts like Einstein’s cosmological constant: it’s an inherent, constant property of any given volume of space itself, regardless of how much the space may have expanded in the past. So we’re apparently safe from a future “big rip” in which the cosmic expansion accelerates so much that stars, planets, and even atoms are torn apart. • The first stars and/or quasars lit up at redshift 10.4 ± 1.2, meaning 460 ± 80 million years after the Big Bang — in reasonable agreement with more direct, astronomical observations. • Not just hydrogen but helium emerged from the Big Bang. This was expected, but it’s the first actual observation of any helium before stars started cooking up more of it — “an important test of Big Bang nucleosynthesis,” says WMAP team member Gary Hinshaw. Meanwhile, the cosmology world awaits news from Europe’s newer Planck probe. It’s up and working well, and its first cosmology results are expected in early 2011. Fo astronomy news as it breaks, see For SkyandTelescope.com/newsblog. Sk
One of the most massive and unstable stars in the Milky Way has brightened ominously in the last year and a half, following a long but slower upward trend. Now about magnitude 4.7, Eta Carinae is fairly easy pickings with the unaided eye from the Southern Hemisphere. When we last left Eta Carinae, researchers were debating whether its 1843 outburst — when it shone nearly as bright as Sirius — resulted from an internal explosion or a radiation-driven blowoff of hot matter from its surface. And with the realization that Eta Car is a binary in a 5.5-year orbit, there’s no way to tell which of its two component stars is causing the trouble — or what will happen next. Recently, the X-rays created where the two stars’ winds slam together strengthened and hardened, “a possible indicator that the star is entering a new unstable phase of mass loss,” says researcher Michael Corcoran. By some estimates Eta Carinae will go supernova within 10,000 years. In other galaxies, such “luminous blue variables”
have exploded abruptly — such as SN 2006jc, which flared in 2004 and then blasted apart two years later. Above is a recent infrared image, taken by the 8-meter Gemini South telescope using adaptive optics, penetrating deep inside the “Homunculus Nebula” of expelled matter around Eta Car.
New Class of White Dwarfs
Fastest Known Binary Star The double stars you can split with an amateur telescope have orbital periods of decades to many millennia, but the shortest binary-star period known is 5.4 minutes. It belongs to HM Cancri, a 21stmagnitude variable star and X-ray source some 16,000 light-years away, which recently proved to be a tightly whirling pair of white dwarfs. The spectrum of HM Cancri clinched it. An international team led by Gijs Roelofs (Harvard-Smithsonian Center for Astrophysics) used the Keck I telescope to detect blue-light emission from hot neutral helium on one star and hotter ionized helium on or around the other star. The two emissions show redshifts and blueshifts that swing back and forth opposite each other with the same 5.4-minute
When NASA scientists unveiled their first transiting exoplanet discoveries from the Kepler satellite (March issue, page 14), they mentioned two weirder creatures that also came up in the net: planet-sized transiting objects hotter than the stars they circle. White-dwarf stars were the obvious suspects. But these two seemed too large to be white dwarfs. The answer lies in their unexpected low masses. Kepler can’t measure an orbiting companion’s mass directly. But two subtle, indirect effects, hidden in Kepler’s extremely precise light curves, showed them to have as little as 0.2 solar mass. That fits with the large diameter Kepler found; low-mass white dwarfs have less self-gravity and so are less compact. Kepler could turn up about 1,000 white dwarfs near normal stars while it searches for Earth-like planets. The Hubble image above shows tiny, faint Sirius B (lower left), one of the smaller, heavier white dwarfs at a mass of 0.98 Suns. If it transited Sirius A (vastly overexposed here) it could be mistaken — briefly — for an Earth. Sk yandTelescope.com June 2010 15
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NASA / H. E. BOND / E. NELAN / M. BARSTOW / M. BURLEIGH / J.B. HOLBERG
Eta Carinae Keeps Brightening
HST (JEFF HESTER) / NASA
In the fringes of the galaxy NGC 1399 lies a globular cluster containing an ultraluminous X-ray source (ULX) thought to be a black hole with a few thousand times the mass of the Sun — a much-sought “intermediate-mass” black hole. New visible-light spectra show that it’s special in another way also. The hot material around it is thick with oxygen and nitrogen while showing no sign of hydrogen. In a globular star cluster, such heavy elements are normally not seen. A team led by James Irwin (University of Alabama) finds one plausible explanation: the black hole recently tore apart an old white-dwarf star that swung too close to it, spilling the white dwarf’s guts. Below, an X-ray image from the Chandra X-ray Observatory (blue) is ULX overlaid on a visible-light image of the elliptical galaxy NGC 1399 (mostly hidden in the X-ray glare).
period as the system’s X-ray variations, confirming that we’re seeing two separate stars in a tight embrace. They’re only about 3 Earth diameters apart, close enough that the larger, lower-mass, cooler star spills a stream of matter onto the smaller, denser, hotter one, heating a small spot to X-ray-emitting temperatures. A double peak in the ionized-helium emission also implies that a hot ring encircles the accreting star, either a belt on its surface or a disk above it. The stars have about 0.55 and 0.25 the Sun’s mass. Their tight whirlabout must make HM Cancri one of the strongest sources of gravitational waves in the galaxy. Says Tod Strohmayer (NASA/Goddard Space Flight Center), “This object is likely radiating more energy in gravitational waves than in electromagnetic energy.”
S&T: CASEY REED
X-RAY: NASA / CXC / UA / J. IRWIN. OPTICAL: NASA / STSCI
A Hole Ripping a Star
2
1
Phobos Landing Sites Imaged The European Space Agency’s Mars Express orbiter made 12 close passes by Phobos, Mars’s inner moon, in February and March. It imaged proposed landing sites for Russia’s Phobos-Grunt (Phobos Soil) mission, which is scheduled to launch in 2011 and return a soil sample to Earth. The close-up above shows two possible sites at a resolution of about 4.4 meters (15 feet). Ground controllers also tracked Phobos’s gravitational effects on the spacecraft with very high precision. Gravity data from earlier flybys showed that Phobos must be 25% to 35% porous, a loose rubble pile. Analysis of the new data could reveal density variations inside the body of Phobos — perhaps large individual caverns, if these exist.
Source of the Zodiacal Light Eerie and elusive, but huge and obvious under good viewing conditions, the zodiacal light appears after dusk and before
ESO / Y. BELETSKY
dawn as a towering but feeble cone of pale light, as seen at right. Under very dark circumstances it can be traced far around the ecliptic. The zodiacal light is sunlight scattering by interplanetary dust grains gradually spiraling their way toward the Sun. But where is the dust coming from? A standard idea has been that half comes from collisions in the asteroid belt and half from the disintegration of short-period comets (which tend to hug the ecliptic). Now we can leave out the asteroids altogether. A five-member team of dynamicists, led by David Nesvorný (Southwest Research Institute), modeled what would happen to dust from asteroid collisions, comets arriving on random orbits from the Oort Cloud, and “Jupiter-family comets” warped into short, low-inclination orbits by Jupiter’s gravity. The short-period comets turn out to account for virtually all of the zodiacal light. The team also considered the situation in the solar system’s youth, when comets should have been abundant. The zodiacal light would then have been hundreds or thousands of times brighter, a lot like the “debris disks” of dust detected around some moderately young stars (see page 26). Even today, the zodiacal light is the brightest thing in the solar system after the Sun (as viewed from a great distance), outshining even Venus. It looks so elusive because it’s spread so thin. Similar “zodi” dust in other planetary systems may prove to be an impediment to imaging Earthlike exoplanets. The twilight picture above was taken last September at the European Southern Observatory’s La Silla site in Chile.
News Note stories are presented in greater depth, with links to further information, at SkyandTelescope.com. Search for the keyword SkyTelJun10.
the data were weak and the analysis took a while, on March 1st NASA announced that LCROSS also detected other volatiles in the debris plume: sulfur dioxide (SO2), methyl alcohol (CH3OH), and diacetylene (H2C4). NASA also announced that its radar instrument on India’s Chandrayaan 1 lunar orbiter found evidence for water ice in more than 40 small craters near the Moon’s north pole. These could hold up to 600 million tons of ice in all. Some of it could be nearly pure, easing the task of water extraction by future lunar colonists. Below is part of the radar map of the Moon’s north polar area. Polarization of reflected echoes shows which craters are fresh (yellow circles) and areas that likely contain water ice (blue circles) in craters’ permanently shadowed floors. ✦
How Much Lunar Water? The most dramatic spaceflight event in the last year was NASA’s October 9th “bombing” of the crater Cabeus, with its eternally dark floor, near the Moon’s south pole. The LCROSS impact kicked up a debris cloud showing spectral signs of water (February issue, page 28). Other evidence has confirmed lunar water molecules over much wider areas (January issue, page 14). There’s more to the story. Although
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PAUL SPUDIS / GEOPHYSICAL RESEARCH LETTERS
ESA / DLR / FU BERLIN (G. NEUKUM)
News Notes
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Cosmic Relief David Grinspoon
Sailing the Solar System In terms of travel time, interplanetary spacecraft can be likened to the sailing ships of old.
People think it’s cool that I’m working on a
ONWARD TO SATURN On October 15, 1997, NASA’s Cassini spacecraft launched aboard a Titan IVB rocket for its 7-year interplanetary cruise to Saturn.
Cassini, the crown jewel of NASA’s current interplanetary fleet, took 7 years after a 1997 launch to reach the Saturn system. The timescales required for sailing ships to cross tens of thousands of miles of ocean in Darwin’s day, and for unmanned spaceships to cross hundreds of millions of miles of interplanetary space today, are similar. Long voyages across empty seas were often punctuated by brief stays in exotic new places. Today, after the adrenaline rush of launch comes the long, lonely interplanetary cruise — only a year or so for the inner planets but a great deal longer for the outer planets — sometimes briefly broken by an exciting encounter with a planet or asteroid. No wonder that some of our interplanetary spacecraft are named Mariner, Viking, Magellan, and Beagle. We desktop explorers don’t have to leave home for years and wonder if we’ll ever see our loved ones again. But there is real risk involved, and sacrifice. People put significant fractions of their lives into missions that might, or might not, return data while they’re still alive. Even when things seem like they’re going right, we can still experience a catastrophic failure at any moment. The payoff during the long years of proposing and planning is that we still get to do work that is mostly fun and interesting and enjoy being part of a community committed to exploration. And we do not endure harrowing storms, high seas, and years of isolation. Even on days when I put in long hours in meetings, telecons, report writing, calculating, and consultation, I can still go home, sit on the couch, watch Star Trek re-runs, and dream of future planetary encounters. ✦
NASA
proposal for a major new NASA Venus mission. But when they ask when it will launch and I answer, “If we’re lucky, perhaps around 2020,” they suddenly appear less enthusiastic, like I’m describing a crazy pipe dream. Maybe you have to be a little bit crazy to do this for a living. At the very least, you need to be comfortable with delayed gratification. Interplanetary spacecraft take a lot of time and work before any metal is cut, and most of them go nowhere. We spend years designing, proposing, and planning missions that never get selected for funding and so never make it anywhere near a launch pad. Because there is no wiggle room in planetary orbits, these projects, once selected, cannot slip schedule without consequence. There is precious little chance of fi xing any mistake discovered after launch. If you make it to launch, you get to enjoy moments of intense anxiety as something you’ve poured years of your life into sits on the pad on a stack of rockets loaded with enough fuel to blow it into shrapnel. At a time when jet travel has shrunk our home planet to within a day’s travel time, planetary exploration requires timescales, and levels of patience, more characteristic of an earlier era of oceanic exploration. Charles Darwin was the naturalist on board the HMS Beagle from 1831 to 1836. His 5-year mission was to explore the strange new worlds of South America and the Pacific, seeking out and cataloguing new life. His discoveries and insights on this voyage repositioned humanity within the web of life on Earth. Now, less than two centuries later, we’re exploring other planets, searching for other sites of Darwinian evolution.
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David Grinspoon is Curator of Astrobiology at the Denver Museum of Nature & Science and author of the recent book Lonely Planets. His website is www.funkyscience.net.
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HST: Discovery Machine
Hubble’s Greatest
Scientific
Achievements
JOHN COYLE, JR
Now that Hubble has been in space 20 years, a leading astrophysicist reflects on its most significant accomplishments.
mario livio
On April 25, 2010, NASA and the worldwide astronomical community celebrated the Hubble Space Telescope’s 20th anniversary in space. Some argue that this telescope has had a similarly profound impact on astronomical research as that of Galileo Galilei’s small telescope 400 years ago. From its perch about 350 miles above Earth, HST has seen farther and sharper than any optical/ultraviolet/near-infrared telescope before it. Unlike astronomical experiments that were dedicated to a specific goal (such as NASA’s Wilkinson Microwave Anisotropy Probe), HST’s achievements generally don’t involve singular discoveries. More often, HST has taken existing hints and suspicions from ground-based observations and turned them into certainty. In other cases, HST has provided a level of detail that forced theorists to revise previous models and construct new ones that would be consistent with the superior emerging data. In a few instances, the availability of HST’s razor-sharp resolution at critical events (such as the impact of Comet Shoemaker-Levy 9 on Jupiter or the aftermath of Supernova 1987A) provided unique insights into specific phenomena. HST has contributed significantly to essentially all areas of current astronomical research, from planetary science to cosmology. As of mid-March 2010, HST has observed 30,322 unique targets, and there are 44.34 terabytes of data in the HST archive. Astronomers using HST data have published 8,736 scientific papers to date, and these papers have generated 323,291 citations. Hubble’s findings are thus far too numerous to be described even briefly in one article. In what follows, I have attempted to concisely review what I regard as the top five scientific discoveries in which HST played a crucial role.
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CAPTURING HST On May 13, 2009, during the fifth servicing mission, Space Shuttle Atlantis astronauts took this picture of the Hubble Space Telescope just after they captured it with their craft’s robotic arm.
1946 Lyman Spitzer conceives the idea of launching a telescope into space.
NASA
In addition to its scientific importance, HST has been a true game-changer in the arena of public outreach and education. It has brought a glimpse of cosmic wonders into millions of homes and schools worldwide, thereby inspiring an unprecedented public curiosity and interest in science. If you ask someone in the public to name a telescope, he or she will almost certainly say “Hubble.” 1977 Congress approves funding for a space telescope.
Dark Energy In 1998 two teams of astronomers working independently presented evidence that the expansion of the universe is accelerating. The evidence was based primarily on the faintness (by about 0.25 magnitude) of supernovae at redshifts of around 0.5, compared to their expected brightness in a universe decelerating under its own gravity.
1978
1979
Astronauts begin training for servicing missions.
1980
Construction of the 2.4-meter primary mirror begins.
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NASA / ESA / ADAM RIESS (STSCI/JHU)
HST: Discovery Machine
DISTANT SUPERNOVAE Many of Hubble’s most important scientific contributions have not involved pretty pictures. Thanks to Hubble’s sharp view, it can pinpoint extremely faint Type Ia supernovae (from exploding white dwarfs) in distant galaxies. Astronomers have combined HST observations with ground-based observations to determine that the universe’s expansion is accelerating, one of the most important scientific discoveries of recent times.
Unless Einstein’s general theory of relativity needs to be modified, the acceleration appears to be propelled by the repulsive force of a mysterious dark energy. Arguably, dark energy’s precise nature is the most profound puzzle that physics is facing today. Since the original discovery, observations of the cosmic microwave background have shown that dark energy currently makes up about 73% of the universe’s energy density. The HST observations relied on Type Ia supernovae (SNe Ia) to trace the universe’s expansion history. There are two properties of SNe Ia that make them well suited for these measurements. First, they are extremely bright and therefore can be observed more than halfway across cosmic time. Second, their luminosities are nearly constant (and the small deviations from constancy can be efficiently calibrated), which makes them excellent “standard candles” — their distances can be determined quite accurately. The HST observations to date have demonstrated three important points: 1. The transition from cosmic deceleration to acceleration occurred around a redshift of 0.5 (about 5 billion years ago). 2. Dark energy was already present 9 billion years ago, though it was not yet dominant. 3. Dark energy’s equation of state (the ratio of its pressure to its density) is consistent with what quantum mechanics predicts for vacuum energy. Many questions still remain. In particular, naïve theoretical attempts to calculate the expected value of the vacuum energy density produce results that are at least 50 orders of magnitude higher than the observed values. 1981
1982
Space Telescope Science Institute established in Baltimore, Maryland.
Consequently, understanding dark energy will require a combination of future observational efforts coupled with significant theoretical developments (S&T: February 2009, page 22).
The Hubble Constant Edwin Hubble, after whom HST is named, was the fi rst astronomer to determine (in the late 1920s) that the cosmos is expanding, following earlier suggestive observations by Vesto Slipher. Just like the rubber of an inflating balloon, the fabric of space between any two distant galaxies is stretching. The current expansion rate is known as the Hubble constant and is denoted by H0. Prior to HST’s availability, determinations of H0’s value were notoriously uncertain, and consequently the universe’s age was unknown to within a factor of two. The main reason for this embarrassing uncertainty was the fact that distance determinations to astronomical objects are extremely difficult. HST’s sharp resolution has
A
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Site of SN 1995al
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STANDARD CANDLES By studying Cepheid variable stars (circled) in spiral galaxy NGC 3021, astronomers pegged its distance at 92 million light-years. In 1995 a Type Ia supernova flared in this galaxy. By knowing the supernova’s distance, astronomers could calibrate its luminosity and compare it to
1983 Space Telescope named for Edwin Hubble.
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1984 Space Telescope European Coordinating Facility established.
1985 Construction of HST completed.
B
C
D NASA / ESA / ADAM RIESS (STSCI/JHU) (5)
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Type Ia supernovae in more distant galaxies. Combining many such measurements, astronomers calculated the universe’s current expansion rate, known as the Hubble constant, to be about 74.2 kilometers per second per megaparsec. This, in turn, yields a cosmic age of 13.75 billion years.
1986
1987
NASA
allowed astronomers to isolate the light from numerous superb distance indicators (Cepheid variables) in dozens of galaxies. Cepheid variables are pulsating stars that are about a thousand times more luminous than our Sun, and their intrinsic brightness is tightly correlated to their pulsation periods. Since the period is relatively easy to measure, astronomers can deduce the intrinsic brightness and thereby the distance. Cepheid observations led to a reduction in the error in the value of H0 to a level of about 10%. In 2009 HST Cepheid observations of the galaxy NGC 4258, whose distance is accurately known from radio observations, coupled with observations of closely monitored supernovae in more distant galaxies in which Cepheids have also been detected, have reduced the error in the value of H0 to less than 5 percent: 74.2 ± 3.6 kilometers per second per megaparsec. When combined with measurements of the cosmic microwave background and of the observed clustering of ordinary matter, this accurate value of H0 has
THE K E Y TO H S T ’ S S U CCE S S HST’s 2.4-meter primary mirror is quite modest by modern standards. But unlike the 8- and 10-meter ground-based telescopes built in recent years, HST gazes from space, far above the distorting effects and skyglow of Earth’s atmosphere. Some of these ground-based scopes are equipped with adaptive optics, which gives them very sharp resolution in the near-infrared, but only for extremely small fields of view in certain areas of the sky. HST is able to achieve a resolution of 0.08 arcsecond (at visible wavelengths) over a much larger field of view, and can observe anywhere on the sky.
allowed scientists to significantly improve the precision of the best constraints on other cosmological parameters such as the number of neutrino species and the cosmic curvature. The universe’s age has been constrained to within 13.75 ± 0.11 billion years (see page 14).
Galaxy Formation and Evolution We’re all familiar with galaxy shapes in the relatively local universe. Disk galaxies such as our Milky Way and Andromeda (M31) appear flattened like pancakes, and they display a prominent spiral structure traced by young, hot stars. Elliptical galaxies are shaped like oval concentrations of relatively old, cooler stars. One of modern astronomy’s goals is to understand how galaxies formed, and how they have evolved to their current state. Astronomers using HST have produced the deepest images of the universe in visible and near-infrared light (January issue, page 24). These “Deep Field” observations have shed light on galaxy evolution all the way back to a time when the universe was only 600 million years old! A few findings are particularly noteworthy: First, galaxies in the distant past were smaller in size and more irregular in shape than present-day galaxies. Both of these properties are consistent with the hierarchical-structure-formation scenario, in which smaller galaxy building blocks collided frequently and accreted cold gas when the universe was smaller and denser. Second, the deep observations allow astronomers to reconstruct the cosmic history of the overall star-formation rate. This rate increased from its value at a cosmic age of 600 million years, reached its peak about 5 billion years after the Big Bang, and has been declining ever since. The present rate is about one-tenth its peak value 9 billion years ago. Third, very early galaxies appear to be extremely blue,
1988
1989
1990 WFPC FOC GHRS FOS HSP
Space Shuttle Challenger tragedy delays October launch of HST. WFPC – Wide Field and Planetary Camera
GHRS – Goddard High-Resolution Spectrograph
FOC – Faint Object Camera
FOS – Faint Object Spectrograph
HSP – High-Speed Photometer
HST launched on April 24, 1990 with 5 instruments (left). Flawed primary mirror discovered.
SOURCE: STSCI / NASA
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NASA / ESA / E. PENG (PEKING UNIVERSITY, BEIJING)
SPIRAL AND ELLIPTICAL HST acquired these images of the two classic types of large galaxies in the local universe: the spiral M81 (above) and the elliptical NGC 4458 (right). HST is helping to unravel the mystery of how these galaxy types came to exist.
as we might expect in a universe in which the metal content (all the elements heavier than helium), and concomitantly the amount of dust, were very low. Finally, HST Ultra-Deep Field observations indicate that early galaxies might have produced sufficient radiation to reionize the intergalactic medium. From cosmic microwave background observations, we know that electrons combined with atoms to form a neutral gas when the universe was about 380,000 years old. There were no sources of light (such as stars and quasars) at that time. As stars, protogalaxies, and perhaps mini-quasars started
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NASA / ESA / G. ILLINGWORTH & R. BOUWENS (UCSC) / HUDF09 TEAM (2)
NASA / ESA / HUBBLE HERITAGE TEAM (STSCI / AURA)
HST: Discovery Machine
GALAXY BUILDING BLOCKS Armed with its new WFC3 camera, HST took an ultra-deep image in August 2009 by staring at a single spot for about 48 hours. Parts of the image revealed several extremely faint blobs (circled, above left and right) that existed about 13 billion years ago, among the most distant objects ever seen. Based on the colors of these blobs, they appear to be small protogalaxies undergoing extremely vigorous star formation.
to appear more than 100 million years later, these sources started to ionize the intergalactic gas in their vicinity. These ionized regions grew, and by redshift of about 6 (when the universe was about 1 billion years old), the reionization of the intergalactic medium was complete, an important phase transition in cosmic history. HST observations of galaxy centers revealed another important fact: Not only do most galaxies harbor supermassive black holes, but the galaxies and the black holes evolve in intimate connection. The black hole masses, which range from about a million to a few billion Suns, are tightly correlated to the masses of the smooth stellar bulges at the centers of galaxies. This relationship indicates that massive black holes are a generic feature of galaxy formation and evolution.
Extrasolar Planets Until 1995 not a single planet outside our solar system had been detected around an ordinary star like our Sun. Since then, however, astronomers have found about 440 exoplanets, and the number is rapidly increasing. Most of these planets were discovered using ground-based telescopes. Nevertheless, HST has contributed a few unique observations to this field, in particular relating to transiting planets. About 70 known exoplanets are transiting planets, meaning they have orbital planes aligned with our line
SERVICING MISSION 1
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1995
HST observes a large
HST discovers a disk fueling
WFPC2 replaces WFPC.
Numerous protoplanetary disks
Release of the famous
storm on Saturn.
a supermassive black hole in
COSTAR replaces HSP and
found in the Orion Nebula.
Eagle Nebula (Pillars of
galaxy NGC 4261.
corrects for the flawed
HST images Comet Shoemaker-
Creation) image.
primary mirror.
Levy 9 impact spots on Jupiter.
WFPC2 – Wide Field and Planetary Camera 2
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COSTAR – Corrective Optics Space Telescope Axial Replacement
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of sight, so that the planets periodically cross the faces of their host stars. Since the planet blocks only a small fraction of the stellar surface, the resulting dimming is typically only by about 1% to 2% (for gas giants). But as the planet passes in front of its star, some of the starlight passes through the planet’s atmosphere, where atoms and molecules absorb certain wavelengths. By observing through filters that isolate particular spectral lines,
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PLANET HUNTER Above right: In February 2004, HST zoomed in near the galactic center and took about 520 images of a small field (boxed). Above left: HST found 16 stars in this field (circled) that appear to be orbited by transiting planets. Most of the stars are so faint that these planet candidates cannot be followed up to determine their masses. EXOPLANET ATMOSPHERE Left: HST took spectra of the star HD 209458. The top spectrum shows the star when its planet was not transiting. The bottom plot shows the difference between spectra taken when the planet was in and out of transit. The pronounced additional dip comes from sodium absorption in the planet’s upper atmosphere.
astronomers can determine the presence and abundance of certain chemicals. HST has thereby detected the atmospheric composition of at least two exoplanets, and more are sure to follow in the near future. HST observations show that HD 209458b’s atmosphere contains sodium, oxygen, carbon, and hydrogen. Similar observations of HD 189733b reveal probable signs of carbon dioxide, water, and methane. In
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distant known galaxy. NICMOS – Near Infrared Camera and Multi-Object Spectrometer STIS – Space Telescope Imaging Spectrograph
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EXOPLANET IMAGED Left: HST took the first image of an exoplanet at visible wavelengths by using an occulting mask to block the blazing light of Fomalhaut. The image captures a dusty debris disk surrounding Fomalhaut. Right: HST pictures taken two years apart reveal the planet’s orbital motion, at a distance of nearly 120 a.u. from the star.
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the case of TrES-1, the transit light curve indicated that the planet had passed in front of a dark spot (similar to a sunspot) on the stellar surface. In another groundbreaking observation, HST has demonstrated that our Galaxy is probably teeming with billions of planets. Astronomers could not have based this conclusion on most of their planet detections, since most of these worlds were found around nearby stars. These results leave open the possibility that the local fraction of planet-hosting stars is atypical of the Galaxy at large. To address this question, HST observed about 180,000 stars in the Milky Way’s crowded central bulge. These obser-
vations led to the discovery of 16 planet candidates, a tally consistent with the frequency of planets in the solar neighborhood. Interestingly, five of these candidates whirl around their host stars in less than one Earth day, and are dubbed USPPs (for Ultra-Short-Period Planets). Finally, HST produced the first direct visible-light image of a planet orbiting another star — the bright southern star Fomalhaut (S&T: March 2009, page 22). The planet, whose distance from Fomalhaut is about 10 times Saturn’s distance from the Sun, was found orbiting inside a large debris disk, somewhat similar to our solar system’s Kuiper Belt.
10 Additional Highlights (From Near to Far): ➊ HST acquired the most
➍ HST discovered that
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detailed images after Comet Shoemaker-Levy 9’s collision with Jupiter in 1994, and the aftermath of the collision of an object with Jupiter in July 2009. ➋ HST discovered two moons of Pluto and took the most detailed images of its surface, showing significant changes over time. ➌ HST discovered a Kuiper Belt object only 1 kilometer across.
protoplanetary disks around young stars are quite common. ➎ HST showed that jets from young stars originate at the centers of the surrounding disks. ➏ HST has provided exquisite images of stellar deaths, including the three-ring structure around Supernova 1987A and still unexplained concentric rings around many planetary nebulae.
populations in nearby galaxies, and has traced these galaxies’ star-formation histories and the galaxy-assembly process. ➑ HST mapped the distribution and movement (from the cosmic web into galaxies) of gas in the nearby universe. ➒ HST imaged the host galaxies of dozens of gamma-ray bursts, showing that long-duration
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GRBs are produced mostly in low-metallicity galaxies, and they are concentrated in regions with massive stars. This supports the theory that long-duration GRBs come from massive stars collapsing to form black holes. ➓ HST has established that quasar hosts are indeed galaxies, and these galaxies are generally either bright ellipticals or interacting galaxies.
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ACS – Advanced Camera for Surveys
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NASA / ESA / PAUL KALAS (UC, BERKELEY), ET AL. (2)
HST: Discovery Machine
Dark Matter
NASA / CXC / STSCI / MAGELLAN / ESO WFI / M. MARKEVITCH / D. CLOWE, ET AL.
Observations of individual galaxies, of clusters of galaxies, and of the cosmic microwave background suggest that most of the universe’s mass is in the form of dark matter — matter that does not emit any light, but which can be detected through its gravitational effects. The best darkmatter candidates are exotic elementary particles that have yet to be discovered with accelerator experiments, and that interact very weakly with familiar particles and with themselves (only through gravity and the weak nuclear force). But astronomers can probe the spatial distribution of dark matter through gravitational lensing — how dark matter’s gravity distorts the images of background galaxies. Just as the images of pebbles at the bottom of a pool appear distorted due to the refraction of light through water, the light of distant galaxies passes through the gravitational influence of intervening clusters, resulting in warped or stretched images. Using HST’s sharp view, astronomers employ this lensing technique to reconstruct the large-scale, three-dimensional distribution of the dark matter responsible for the distortions. In one study, astronomers constructed the distribution of dark matter (in one direction) 3.5, 5.0, and 6.5 billion years ago. They found that dark-matter clumping becomes more pronounced over time. Astronomers have also used HST to observe the dark matter’s distribution in the collision of two clusters of galaxies, one seen pole-on and the other from a direction perpendicular to the collision axis. In the latter case in particular (known as the Bullet Cluster), a combination of HST and Chandra X-ray observations suggests that the hot gas in the two clusters interacts strongly, producing a shock front, while the dark matter completely separates from the gas. This is precisely what we expect from very weakly interacting particles, which is what leading theories predict for dark matter.
DARK MATTER IMAGED Dark matter doesn’t radiate or absorb light, but HST and other telescopes can sense how its gravity distorts the shapes of background galaxies by gravitational lensing. This image of a large galaxy cluster known as the Bullet Cluster (which is undergoing a collision) combines HST optical observations with Chandra X-ray observations and ground-based data. Chandra reveals hot, X-ray-emitting gas (red) and HST helps map the dark matter (blue). The gas and dark matter have clearly separated, which is what theorists predict if dark matter is comprised of elementary particles that interact very weakly with familiar matter.
allowing for a better understanding of dark energy. The Cosmic Origins Spectrograph will probably reveal to us the structure and composition of the “cosmic web” — the filamentary gas that permeates intergalactic space. One thing is virtually certain: we will have to revisit the list of the top HST achievements for Hubble’s 25th anniversary! ✦
The Future
Astrophysicist Mario Livio is Head of the Office of Public Outreach at the Space Telescope Science Institute, which conducts the Hubble Space Telescope’s scientific program. He has published more than 400 scientific papers on a wide range of topics in astrophysics, and has received numerous awards for his research, teaching, and books. The Washington Post selected his popular science book, Is God A Mathematician?, as one of the best books of 2009.
During Servicing Mission 4 in May 2009, astronauts equipped HST with the largest and most advanced complement of functioning instruments it has ever had (S&T: October 2008, page 26). Consequently, the telescope’s future surely portends many exciting discoveries. In particular, Wide Field Camera 3 could detect SNe Ia at even larger distances, which will help tame potential evolutionary effects in the characteristics of these explosions, thus
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out to redshifts higher than 8. HST images show dramatic COS – Cosmic Origins Spectrograph
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Cosmic Trails 2
OBSERVING THE SKY A Second Century for Mount Wilson Observatory Speaker: Hal McAlister , Ph.D. With its 60- and 100-inch night-time telescopes and 60- and 150-ft solar tower telescopes, Mount Wilson Observatory (MWO) reinvented astronomy and gave birth to “astrophysics” early in the 20th century. While MWO is most certainly a world heritage science site, it is by no means an astronomical relic. Its excellent seeing conditions, enabled by stable air off the cold Pacific Ocean, make the site a great location for modern work emphasizing high resolution of stars by night and the sun by day. Join Dr. McAlister on a virtual insider’s tour of MWO facilities and learn all about plans for “America’s Observatory.”
Eastern Caribbean, March 6th – 13th, 2011
Choosing and Using a Telescope Speaker: Alan Dyer Thinking of buying a new telescope? Alan walks us through the marketplace of hundreds of telescopes, suggesting what to look for to ensure you get a great telescope you’ll use a lot! Or … are you perplexed by the telescope you already own? Alan dispels myths and misconceptions many telescope owners still hold, and reviews tips and techniques all telescope owners should know.
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Expand your horizons, enrich your practice of astronomy, and relax with friends and kindred spirits. Join Sky & Telescope on the Cosmic Trails 2 cruise conference on Holland America’s Nieuw Amsterdam, March 6–13, 2011. Expert knowledge, lush islands, recreation, and reflection await you. Cosmic Trails balances the complexity and intricacy of modern astronomy with the simplicity of cruise travel. Get the big picture on the search for solar systems and planets with Dr. Alan Boss. Take a practical look at the instruments and photographic tools and techniques that can boost your observing productivity and enjoyment with Alan Dyer. Draw more information from celestial bodies right before your eyes with Captain Steve Miller’s primer on celestial navigation. Visit the unseen world of radio astronomy
and the future of superscopes with Ivan Semeniuk. Get an account of Mount Wilson’s epic activities and learn about the contributions of small telescopes in astronomy today with Dr. Hal McAlister. And then, recharge your batteries in port, with kayaking, a chilled-out bistro lunch, or a great day at the beach. Go on an optional jaunt to Arecibo Observatory — glimpse the Gregorian dome and go behind and under the scene. Sail with Sky & Telescope and indulge your thirst for knowledge. Have quiet time with a friend; enjoy fun and camaraderie with fellow astronomers; take your astronomy skills and knowledge up a notch. Visit www.In SightCruises.com or call Neil or Theresa at 650-787-5665 to get all the details, and then enrich your astronomy routine with an intellectual adventure with the Sky & Telescope community.
Small Telescopes in the 21st Century Speaker: Hal McAlister , Ph.D. Astronomers now tag optical telescopes with apertures of 4 meters and below as “small” telescopes, and the trend is to design and build super telescopes with apertures of 30 meters or even larger. So, do “small” telescopes still have a role? We’ll look at that question by exploring issues like scientific productivity, ease of access, cost of operation, developing new instrumentation, and student training. Dr. McAlister will highlight examples of innovative new ways of using small telescopes and their impact on astronomy. The Power and Progress of Radio Astronomy Speaker: Ivan Semeniuk
Superscopes: The Future of Cosmic Exploration Speaker: Ivan Semeniuk More than four centuries since Galileo first turned a telescope to the heavens, the primary tool of astronomers is continuing to evolve and grow. Plans are underway for giant mountaintop observatories, like the Thirty Meter Telescope (TMT), that will usher in a new era of astronomical discovery. From the light of the first stars to the search for life on other worlds, we’ll explore the scientific questions that are driving the next generation of big telescopes, and generations to come.
Near Arecibo, Puerto Rico, the world’s largest dish antenna points skyward and tunes us into to the radio universe. Whether it involves probing the nearest asteroids or spotting the most distant galaxies, radio astronomy has created a crucial window into the cosmos — and it remains our most likely channel for contact with other civilizations. Join Ivan and find out how radio astronomy is moving to the next level at Arecibo and new facilities around the world. Discover a universe that is forever unseen by human eyes. CST# 2065380-40
Cruise prices start at $899, per person, for an Inside Stateroom. For those attending our seminars, there is a $1,375 fee. Taxes and fees are $129 per person.
NASA’s KENNEDY SPACE CENTER: AN INSIDER’S VIEW
For more info contact Neil at 650-787-5665 or
[email protected]
NASA’s launch headquarters, on the Space Coast, is the only place on Earth where you can tour launch areas, meet a veteran astronaut, and grasp the true enormity of the Space Program. Experience fun and wonder with Cosmic Trail companions in this private pre-cruise, custom, full-day tour. Get ready to walk among and beneath giant rockets, discover what it takes to launch the Space Shuttle from preparation to liftoff, and soak in Kennedy Space Center’s “The Right Stuff ” vibe. We’ll have an intense day with our expert guides, integrating the touchstones and experiences every visitor wants with behind-the-scenes sites seldom accessible to the public. The LC 39 Observation
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Gantry, International Space Station Center, Apollo/ Saturn V Center, and Astronaut Hall of Fame are on the agenda. We will not only view but visit the Vehicle Assembly Building, the shuttle landing strip, and the 6-million-pound crawler that transports the shuttle. Do lunch with an astronaut, view IMAX films with footage shot during NASA missions, and enjoy the products of mankind’s inspiration. The Kennedy Space Center excursion is $225; it includes all of the above plus dinner, and transportation from the Kennedy Space Center to our pre-cruise hotel in Ft. Lauderdale. For details/ questions, please contact Neil or Theresa, or give us a call at (650) 787-5667.
SHOOTING THE SKY
Processing Images, the Finishing Touch Speaker: Alan Dyer
In making a great deep-sky photo, the secret of success is in the image processing. Alan will step us through his “workflow,” from file transfer from Digital single lens reflex (DSLR) cameras have the camera to final publication-grade photo. The revolutionized astrophotography, providing powerful workflow stays entirely within the Adobe Photoshop cameras the rest of us can actually afford and use. In family of programs, including Adobe Camera Raw. a three-part workshop Alan takes us through all the By taking a set of images “from RAW... to remarkable” steps for taking great photos suitable for publication Alan demonstrates the wonderful but little-known in Sky and Telescope! In this session Alan reviews tools Adobe Photoshop offers for astronomers. what to look for in a DSLR camera for astrophotography. Once you have a camera, you’re ready to take publication-quality photos with no more than surprisingly simple techniques. Alan presents his suggestions for shooting great nightscapes and stunning time-lapse sky movies. Choosing and Using a DSLR Camera Speaker: Alan Dyer
WITHIN OUR SOLAR SYSTEM The Formation of Our Solar System Speaker: Alan Boss, Ph.D.
New Voyages to Mercury, Mars, and the Asteroid Belt Speaker: Ivan Semeniuk
2011 will be a banner year for the exploration of the inner solar system, including the first missions to Discoveries have confirmed long-held suspicions that orbit Mercury and the first encounter with a major a supernova or other energetic stellar wind may have asteroid (Vesta). It will also bring the launch of directly triggered the formation of our solar system. NASA’s Mars Science Laboratory, the most ambitious The Sun appears to have been born in a region where robotic lander ever. Upcoming missions will answer many stars were forming, many of them massive key questions that address our emerging picture of rocky planets, including their origins, diverse enough to explode as supernovae. Given that most histories and role in fostering the emergence of life. stars are thought to form in similar environments, Ivan will review the science behind these missions the fact that our solar system supports life implies and bring you up to date on the reconnaissance of that similar planetary systems, and hence life, may our neighboring worlds. be commonplace in thegalaxy.
BEYOND OUR SOLAR SYSTEM
Twenty Five Years of Seeing Double Speaker: Hal McAlister, Ph.D.
The Search for Living Planets Speaker: Alan Boss, Ph.D.
Speckle interferometry, discovered by Antoine Labeyrie in the early 1970s, is the simplest means for coping with atmospheric blurring and reaching the full diffraction limit of a telescope. Speckle interferometry has now replaced visual micrometry as the standard means for observing “visual” binaries. Hal earned his spurs as an astronomer tailoring the method to accurately measuring binary stars. He will describe the method and take you on a visit to some of his old friends among the double stars.
What are the chances that life exists elsewhere in the universe? The expectation is that most sun-like stars will harbor habitable worlds, and that life will be commonplace in our galaxy, and throughout the universe as well. NASA’s Kepler Mission will determine the frequency of Earth-like planets by 2013. NASA will build other space telescopes that will discover the Earth-like planets closest to our Solar System, and characterize their atmospheres. The detection of biomarkers may allow us to determine whether these worlds are not only habitable, but perhaps even inhabited. A Journey to the Center of the Milky Way Speaker: Ivan Semeniuk The greatest attraction of the tropical sky is not a single star or constellation but the view it affords of the center of the Milky Way. Shrouded in interstellar dust, the exotic environment at our galaxy’s hidden core is only now being revealed with the power of space-based astronomy. This session puts Caribbean stargazing in perspective with a cutting-edge trip to the galactic center, where astronomers are hunting for dark matter, tracking the flight of hypervelocity stars, and peering over the event horizon of a supermassive black hole.
Zooming in on the Stars Speaker: Hal McAllister, Ph.D. Stars are so distant that only a handful of supergiants are within the resolution limit ideally obtained by large telescopes. The only way of measuring the sizes of normal stars and to resolve the tightest binary star systems is to observe them with multiple telescope, long-baseline interferometers. The premier instrument of this type for stellar astronomy at present is the CHARA Array, an array of six 1-meter telescopes laid out on the grounds of Mount Wilson Observatory. We’ll follow the paths of photons traveling through an interferometer, where they encounter dozens of mirrors, filters, and optical windows before they combine and do their high resolution magic. Join Hal McAllister for a look at the unique contributions long-baseline interferometry is making to our knowledge of stellar properties.
Tips and Techniques at the Telescope Speaker: Alan Dyer Hook a camera to a telescope and you have a powerful combo for taking long exposures of deep-sky targets. Alan gives you recommendations for camera settings for maximum performance, how to find and focus targets, and whether to guide or “track-and-stack” short exposures.
CELESTIAL NAVIGATION
The Basics of Latitude and Longitude Speaker: Steve Miller
Introduction to this series of six classes: This hands-on, six-hour class (three of which are described here) is about determining your exact position on Earth — using the celestial bodies visible in the sky as your references. This seminar will cover the tools used for celestial navigation, primarily the sextant and an accurate timepiece. The coordinate system of both the Earth and the sky will be explained as will the relationship between longitude and time. The navigator’s traditional Noon Sight will be discussed and the procedures will be explained and demonstrated.
This session will cover the basics of latitude and longitude on Earth and the coordinate system used in the sky. For the Sun, in our discussions, we will discuss the declination (latitude) and the Greenwich Hour Angle (longitude) and their relationship to the latitude and longitude on Earth. The attendees will get an understanding of the basic relationship of the coordinate systems on Earth and the sky along with the importance of time.
The Tools Used in Celestial Navigation Speaker: Steve Miller In this session the tools used in celestial navigation will be discussed. There will be a hands-on exercise with the sextant in the classroom and in a later session it will be used to do an actual sight of the Sun. The Nautical Almanac will be introduced and the pertinent information that is required for the sight will be revealed.
ARECIBO OBSERVATORY: A BEHIND-THE-SCENES TOUR Explore the contributions and potential of radio astronomy at the celebrated Arecibo Observatory. Get an unparalleled behind-the-scenes tour of the iconic facility, and absorb an in-depth look at the unique contributions derived from Arecibo research and development. Join us as we wind through the rainforest-blanketed karst terrain of Northern Puerto Rico. We’ll get a sense of the massive physical scope of the Arecibo radio telescope. We’ll boldly go where ordinary visitors are not permitted. NAIC scientists will update us about the radio astronomy, planetary radar discoveries, and climatology research at the observatory. From the monitoring of near-earth
We will learn about the two types of Sights that we will be doing our cruise, the Noon Sight, and a Polaris Sight. The Noon Sight actually takes place at a specific time of the day determined by the rotation of the Earth around its axis. We will learn how to determine the Noon Sight time and what we do with the information after our Sight. The Polaris Sight can be done before sunrise or after sunset and we will learn how to determine exactly when you can “shoot” Polaris.
Photograph Courtesy of the NAIC-Arecibo Observatory, a facility of the NSF
objects to cosmology, astrophysics, and global warming research, you’ll gain insight into the vital activities at Arecibo. Optional eight-hour tour includes transportation, entrance fees, and a private luncheon at the Arecibo Observatory ($175). Transmission of the Arecibo message to star cluster M13 in 1974 marked the remodeling of the telescope we’ll be visiting. The 73-row-by-23-column message depicts numbers, aspects of DNA, graphic depictions of humans, the solar system, and the Arecibo telescope.
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The Two Types of Navigator’s Sights Speaker: Steve Miller
© Chris Campbell
Exploring the Pluto System
NEW HORIZONS:
WAY HISTORIC
HALF to a
ENCOUNTER s. alan stern
In January 2006, NASA’s New Horizons spacecraft sped away from Earth as the fastest spacecraft ever launched. Earlier this year, New Horizons passed the halfway point to its far-flung primary target, the Pluto system. In March 2011, the craft will pass the orbit of Uranus and begin the last long leg of its cruise — the almost billion-mile journey across the space between Uranus and Neptune. New Horizons will reach the Pluto system — more than 3 billion miles from home — on July 14, 2015, fifty years to the day after NASA’s Mariner 4 mission inaugurated the close-up imaging of the planets with its Mars flyby. And in the months and weeks surrounding the Pluto close approach, New Horizons will reconnoiter the dwarf planet and its retinue of three known moons in greater detail than any previous first flyby of a planet by any spacecraft. After completing its tasks at Pluto, New Horizons will fire its engines and change course to make the first of
what will hopefully be two flybys of small (25- to 30-milewide) but ancient Kuiper Belt objects (KBOs). The exploration of the terra incognita of the Kuiper Belt and its most famous planet will provide important insights into the formation history of the giant planets, the architecture of our solar system, the nature of comets, and even the manner in which Earth and Mars may have acquired water and other volatile compounds. Moreover, New Horizons will reveal the nature of a new and populous class of planets — the ice dwarfs, which have never been explored despite 50 years of robotic surveys of the terrestrial and giant planets. By the time New Horizons completes its mission in 2019 or 2020, it will have opened up our system’s third and most distant region to spacecraft exploration and, we hope, rewritten textbooks.
Packing a Powerful Punch NASA conducted a competition for a Pluto–Kuiper Belt mission in 2001, out of which New Horizons was selected. In 2003 Congress and NASA approved New Horizons for full-scale development. Its goals are simple: to fly by Pluto and its large moon Charon, and to go on to explore small KBOs that were formed during the birth of the planets.
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PHOTO OF AUTHOR: MICHAEL SOLURI
An intrepid NASA spacecraft is speeding toward its June 2015 rendezvous with Pluto.
PLUTO FLYBY S&T artist Casey Reed portrays New Horizons’ July 14, 2015 close flyby of Pluto, with Charon looming in the distance. Nobody knows what Pluto will look like when we view it up close, but given the track record of past planetary encounters, scientists expect to be surprised.
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Exploring the Pluto System
NASA required the mission to carry out three fundamental objectives: fully map Pluto and Charon in both panchromatic and color channels, map the surface compositions of Pluto and Charon, and assay the composition, structure, and escape rate of Pluto’s atmosphere. NASA also set as goals (though not requirements) that the mission search for additional satellites and rings in the Pluto system, provide stereo coverage to map topography, measure temperatures across Pluto and Charon, probe Pluto’s ionosphere, and search for an atmosphere around Charon. Since those goals were set, a team I co-led with Hal Weaver discovered Pluto’s small moons Nix and Hydra, and the New Horizons team and NASA have added their exploration to the objectives. During a six-month-long observation period as New Horizons flies up to and past the Pluto system, the spacecraft and its eight-instrument scientific payload will accomplish all of these objectives. Our team also plans to map both the geology and surface composition of Nix and Hydra, refine the radii and masses of Pluto, Charon,
4 FOR THE PRICE OF 1 When New Horizons reaches its primary destination, it will encounter four objects: Pluto and its three moons. This Hubble Space Telescope image shows, from left to right, Pluto, Charon, Nix, and Hydra. New Horizons will enable astronomers to test the leading theory that the three moons formed billions of years ago after a large object smashed into Pluto. NASA / ESA / HAL WEAVER (JHU APL) / ALAN STERN (SWRI) / HST PLUTO COMPANION SEARCH TEAM
Nix, and Hydra, and assay the charged particle, dust, and space plasma environment near Pluto and even deeper in the Kuiper Belt. New Horizons will accomplish all of this in a spacecraft not much larger than a piano and weighing (with its fuel supply) just under 1,000 pounds. Inside this small package lie fully redundant computing, guidance, communications, propulsion, and power distribution systems, star trackers, gyros, a nuclear-power generator, and eight instruments. The spacecraft can store up to 160 gigabits of information on its recorders and can point to accuracies of better than 1 arcsecond for imaging. The eight instruments include two imagers, two spectrometers, two plasma/charged particle instruments, a radio science package, and a dust counter to survey interplanetary space across the solar system. Thanks to
New Horizons’ Eight Instruments Ralph MVIC
LORRI
Multicolor Visible Imaging Camera Panchromatic mediumresolution imaging and color imaging in blue, red, methane, and near-infrared bands at moderate resolution.
Long Range Reconnaissance Imager Telescopic camera that will obtain encounter data at long distances, will map Pluto’s farside, and provide high-resolution geologic data on the encounter hemisphere.
Ralph LEISA Linear Etalon Imaging Spectral Array Near-infrared imaging and spectroscopy; will provide composition and thermal maps.
SDC Student Dust Counter Built and operated by students; it measures the space dust peppering New Horizons during its interplanetary voyage.
NASA
SWAP
SMALL SPACECRAFT Technicians from the Applied Physics Laboratory, working at NASA’s Kennedy Space Center, install a panel while preparing New Horizons for launch. The spacecraft is not much bigger than a piano.
Solar Wind Around Pluto Solar wind and plasma spectrometer; will measure atmospheric escape rate and observe Pluto’s interaction with the solar wind.
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Alice Ultraviolet Imaging Spectrometer Will analyze composition, structure, and escape rate of Pluto’s atmosphere and will look for atmospheres
around Charon and Kuiper Belt objects.
PEPSSI Pluto Energetic Particle Spectrometer Science Investigation Energetic particle spectrometer; will measure the composition and density of ions escaping from Pluto’s atmosphere.
REX Radio Science Experiment Will measure atmospheric pressure and temperature; also serves as a passive radiometer for thermal studies and will refine the masses of Pluto and Charon.
the march of technology, the New Horizons payload will carry out a powerful and prolonged investigation of the Pluto system, far exceeding what the Voyager 2 spacecraft accomplished when it reconnoitered the Uranus and Neptune systems in the 1980s.
Launch from Earth Jan. 19, 2006 Saturn
The Main Event New Horizons is the first in NASA’s New Frontiers series of planetary missions. In February and March 2007, barely a year after launch, the spacecraft conducted a Jupiter flyby that boosted its speed and accomplished more than 700 scientific observations of Jupiter, its Galilean moons, its ring system, and its magnetosphere. More than three years later, the craft remains on course and in extremely good health. None of its backup systems have been needed, and each of its scientific instruments is operating at or above specification. The craft is carrying a healthy fuel reserve that will enable a long Kuiper Belt mission as the spacecraft flies from 32 astronomical units (a.u.), where Pluto will be encountered, to 55 a.u., where the Kuiper Belt population sharply drops. But New Horizons’ main event will be its Pluto-system encounter. We will map all of Pluto and its moons in both color and black and white, map their surface compositions, map their surface temperatures, and study their surface reflectance properties as a function of location. Geological maps, with resolutions as sharp as 1 kilometer, will be of higher quality than any maps ever produced on a first reconnaissance flyby of a planet. Moreover, we’ll obtain high-resolution imagery of selected portions of Pluto with resolutions of almost 100 meters. New Horizons will assay the temperature and pressure of Pluto’s atmosphere and determine the mole fractions of its constituent gases down to levels of a few percent. We’ll attempt to measure the atmospheric escape rate and the composition of escaping ions, and we will carefully search for atmospheric clouds, hazes, and geysers. And in a dramatic experiment as we depart, we’ll image Pluto’s night side as it’s illuminated by the soft glow of Charon-light. Our mission team has already completed the detailed planning of the most intensive portion of the encounter, a rapidly paced nine days that includes the July 14th closest approach to within 10,000 kilometers of Pluto’s surface. The team has also completed the basic architectural planning of the approach and departure phases that stretch across all of June and July 2015, as well as the surrounding distant approach phases that begin in January 2015 and continue until the close approach begins in June. Altogether, New Horizons will be studying the entirety of Pluto and its moons — from January through July 2015. That’s no “weekend at Pluto,” it’s a long and intensive study of the entire Pluto system, its environment in space, and perhaps bodies that we have not yet discovered, such as new small moons.
Uranus Jupiter system close approach Feb. 28, 2007 Neptune
Not to scale. Planet positions shown at time of launch.
Pluto system flyby July 14, 2015
Pluto
THE PATH TO PLUTO New Horizons will travel 3 billion miles (4.8 billion km) over 8 years to reach its main objective: the Pluto system.
Kuiper Belt object encounters 2016 – 2020
S&T: GREGG DINDERMAN
Shedding Light on Pluto’s Atmosphere Astronomers had long suspected that Pluto has an atmosphere, and that it might even bulk up and decline during Pluto’s eccentric, 248-year orbit. But proof that Pluto “has air” finally came in 1988 when Jim Elliot (MIT) observed light from a faint star being refracted above Pluto’s surface as the star crossed behind Pluto during an occultation. That first occultation showed us that Pluto’s atmosphere is about twice as warm as the surface, exhibits evidence of hazes, and may even be capable of escaping so fast that many kilometers of icy terrain have been eroded into space over geologic time. Since then, astronomers have observed another dozen occultations. These events have revealed that Pluto’s atmospheric pressure — measured to be just a few tens of microbars — has been increasing, perhaps by as much as a factor of three since 1988. They’ve also revealed evidence for atmospheric waves and other interesting dynamical phenomena. And recent occultations have provided evidence that Pluto’s atmosphere may even be lopsided. New Horizons’ sophisticated visible mappers and radio and ultraviolet instruments will provide the first unambiguous measurements of Pluto’s atmospheric pressure, return precise details of the planet’s atmospheric structure and composition, and determine the extent of hazes and clouds around the Plutonian globe. But perhaps most exciting will be the atmospheric discoveries New Horizons makes that are wholly unexpected, for that is what great voyages of exploration are all about.
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Exploring the Pluto System
RED SPOT: NASA / JHU APL / SWRI IO: NASA / JHU APL / SWRI / S&T: SEAN WALKER
suggested by the public. The specific observations we have planned were proposed after we solicited input from advanced amateur planetary scientists who are members of the “Unmanned Spaceflight.com” chat site. These observations include family portraits of Pluto and its retinue of moons, and shots of Charon’s crescent near Pluto’s limb.
Fasten Your Seatbelts
JUPITER ENCOUNTER New Horizons flew by Jupiter on February 28, 2007, with a closest approach of 1.43 million miles. New Horizons received a gravitational assist, boosting its velocity away from the Sun by nearly 9,000 miles per hour and yanking it about 2.5° out of the ecliptic plane. During the encounter, New Horizons took these images of Jupiter’s Great Red Spot (left) and large moon Io (right).
NASA
The encounter will investigate the processes that shape the surfaces of dwarf planets and drive their interior activity, how surface composition varies across dwarf planets, and the nature and extent of activity on dwarf planets. New Horizons will shed new light on the process of hydrodynamic atmospheric escape, which likely operates on Pluto and other dwarf planets with atmospheres, and which possibly occurred on the young Earth. One unique aspect of the encounter is a series of observations of Pluto and its moons at opportune times
LIFTOFF! New Horizons launched aboard an Atlas V rocket from Cape Canaveral Air Force Station on January 19, 2006. When the last engine shut down, the spacecraft was traveling 36,373 miles (58,537 km) per hour relative to Earth, a speed so fast that it reached the Moon’s orbit in only 9 hours.
Download a FREE BONUS PODCAST To hear a podcast interview with author Alan Stern, visit SkyandTelescope.com/ newhorizons.
After reconnoitering the Pluto system, New Horizons will spend the next five years traversing the Kuiper Belt. We have sufficient fuel to fly by one or two Kuiper Belt objects near our trajectory. The search for these KBOs is on now, and we hope to identify candidate flyby targets by 2012, though we will gather more data before we select our actual flyby targets in 2015. When we fly by our KBOs, we’ll approach as close as possible — perhaps within 25,000 kilometers, and we’ll make the same kind of surface and atmospheric studies that we plan for Pluto. In fact, all of our scientific instruments have been designed to deliver good results as far as 55 a.u. from the Sun. As you read these words, we’re still more than 1,800 days and 15 a.u. from beginning the Pluto encounter in early 2015. But we’re now more than halfway to our goal. And our spacecraft will perform flyby rehearsals in 2012 and 2013, and we have allotted reserve time for a backup rehearsal in 2014, if necessary. If all goes as planned, by the middle of this decade, NASA spacecraft will have marched their way across all nine classical planets, reconnoitering them one by one, and in doing so, they will have opened our eyes and minds to the richness and diversity of planetary types in our solar system. This mission of bold, first-time exploration of new frontiers has already captured the imagination of countless children and citizens about the beauty of nature and the power of technology to do good things. Today, New Horizons traveled almost a million miles closer to its goal, as it will do again tomorrow and the next day and the next. Fasten your seatbelts! The exploration of a whole new class of planet will be coming your way later this decade! ✦ S. Alan Stern is a planetary scientist at the Southwest Research Institute and the principal investigator of New Horizons. He was formerly NASA’s associate administrator leading all space and Earth sciences programs. He is coauthor (with Jacqueline Mitton) of the book Pluto and Charon.
Visit these websites for more information about New Horizons: ht http://pluto.jhuapl.edu ht http://www.nasa.gov/mission_pages/newhorizons/main/index.html ht http://www.youtube.com/watch?v=W77ubwHwOMo
34 June 2010 sky & telescope
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Some of the catadioptric telescopes we carry . . . 25 Telescopes
Meade has been in the telescope business for 38 years and making catadioptric scopes for backyard astronomers since 1980. Astronomics has been proudly selling Meade scopes for 30 of those years. Here are the Meade catadioptrics (flat field Advanced Coma Free ACF, Schmidts, and Maksutovs) that we carry. All come with go-to computer, finder, eyepiece, tripod, and more. Meade ETX, two models, 3.5” and 5” Maksutovs: dual fork go-to altazimuths, 30,000 object AutoStar computer. $499 to $699. Meade LT, two models, 6” ACF and Schmidt: single fork arm go-to altazimuths, 30,000 object AutoStar computer. $999 to $1099.
Meade LXD-75, one model, 8” Schmidt: go-to German equatorial, 30,000 object AutoStar. $1399. Meade LS, four models, 6” and 8” ACF and Schmidt: single fork arm goto altazimuths, 30,000 object LightSwitch self-aligning computer. $1399 to $1999. Meade LX-90, six models, 8” to 12” ACF and Schmidt: dual fork arm goto altazimuths, 30,000 object AutoStar computer. $1799 to $3299. Meade LX200-ACF, eight models, 8” to 16” ACF: dual fork arm go-to altazimuths, 147,500 object AutoStar computer. $2599 to $16,299. Meade LX400-ACF, two models, 20” ACF: go-to German equatorial, 147,500 object AutoStar. $34,999.
Meade LS8 ACF LightSwitch 8” f/10 ACF, complete and ready to observe
27 Telescopes Celestron developed the first catadioptric telescope for backyard astronomers 50 years ago, ushering in the age of affordable big aperture astronomy that we all continue to enjoy to this very day. Astronomics has been a proud partner with Celestron for 31 of those years. We carry 54 Celestron scopes. Of that 54, 27 are Edge HD, Schmidt, and Maksutov catadioptrics. All are ready to start observing right out of the box. Here are those 27 scopes . . . Celestron NexStar SLT, two models, 3.5” and 5” Maksutovs: go-to altazimuth mounts, 4,000 object SkyAlign computer, flashlight battery operation. $499 to $549. Celestron Omni XLT, one model, 5” Maksutov: manual German equatorial mount (can be motorized for flashlight battery operation). $699. Celestron NexStar SE, four models, a 4” Maksutov, plus 5” to 8” Schmidts: single fork arm go-to altazimuths, 40,000 object Sky-Align computer, flashlight battery operation.
$499 to $1199. Celestron GT Advanced, four models, 6” to 11” Schmidts: go-to German equatorials, 40,000 object Sky-Align computer. $999 to $2399. Celestron CPC, three models, 8” to 11” Schmidts: dual fork arm go-to altazimuths, 40,000 object Sky-Align computer. $1999 to $2799. Celestron CGEM, three models, 8” to 11” Schmidts: 40 pound payload goto German equatorials, 40,000 object Sky-Align computer. $2099 to $2999. Celestron CGEM HD, three models, 8” to 11” flat-field Edge HD: 40 pound payload go-to German equatorials, 40,000 object Sky-Align computer. $2399 to $3499. Celestron CGE PRO, four models, 9¼” to 14” Schmidts: 90 pound payload go-to Ger man equatorials, 40,000 object Sky-Align computer. $5999 to $9499. Celestron CGE PRO HD, three models, 9¼” to 14” flat-field Edge HD optics: 90 pound payload go-to German equatorials, 40,000 object SkyAlign computer. $6299 to $9999.
15 Telescopes Questar has been making ultrapremium Maksutov-Cassegrains in the United States for 60 Years. We’ve sold Questar for 30 of them.
Questar, fifteen models, 3.5” to 7” Maksutovs: optical tubes and dual fork arm altazimuths convertible to equatorial, $4250 to $12,449.
$1999
In addition to these fine Meade, Celestron, and Astro-Tech telescopes, Astronomics also carries catadioptric scopes from Questar, Takahashi, and more.
Clear skies . . . from our family to yours. Astronomics has been a family business since my wife June and I started it in 1979, 31 years ago. Son Michael has been part of the business since he started keeping our inventory on filing cards in ’79 at age 7. He’s been the guiding force behind Astro-Tech, our ever-growing optics manufacturing company. Grandkids Liam and Ellie, right, are a little too young to join the business, but telescopes fascinate them, so it won’t be long. We’ve been lucky, because we’ve been able to make a living doing something we love. May you have the same luck.
astronomics
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Celestron’s Golden Anniversary
dennis di cicco The entrepreneurial spirit of one amateur astronomer led to the creation of a legendary telescope company.
Celestron, one of the world’s best-known names in telescopes, is marking 2010 as its 50th anniversary year. While other telescope companies have reached this milestone, Celestron stands out for its current success (company president and CEO, Joseph Lupica, reports that 2009 was Celestron’s second best year ever) and a continued commitment to its founding vision on of serving the astronomy community, especially “serious” amateurs. Indeed, the 5-, 8-, and 14-inch Schmidt-Cassegrain telescopes that set the course for Celestron’s future in the early 1970s are still flagship instruments in the product line. But they were re not the scopes that launched the brand. For those, we need to step back another decade. Thomas J. Johnson, Celestron’s founder and the genius behind the modern Schmidt-Cassegrain telescope, was in his early 30s when he used his World War II experience as a radar technician and post-war employment in the electronics industry to establish Valor Electronics in 1955. Based in Gardena, California, Valor made a variety of components for military and industrial customers, and by the early ’60s it had expanded to roughly 100 employees. As Valor was growing, so too was Johnson’s interest in amateur astronomy. First purchasing 4- and later 10-inch Newtonian reflectors from Cave Optical — one of the preeminent brands in North America during the ’50s — Johnson then headed down a path followed by many amateurs of the day and turned to the hobby of telescope making. In 1960 he established the Astro-Optical division
Thomas Johnson’s transportable transport 18¾-inch Cassegrain refl ector was such a sensation at the Los Angeles Astroreflector nomical Society’s Mount Pinos star party in July 1962 that it was featured as this magazine’s cover story the following March. The scope played a pivotal role in Johnson’s decision to launch the company that became Celestron.
of Valor. His first scope was an 8-inch f/4 “rich-field” Newtonian, and it was soon followed by a 12-inch Cassegrain. His next project, however, was a highly unconventional 18¾-inch Cassegrain made to be transportable. To reduce the weight of the 3-inch-thick primary mirror, Johnson had a ribbed pattern sandblasted into the back of the glass blank. Six months and about $1,000 later, he had a fork-mounted scope that could be disassembled and packed into a car in about 15 minutes. On July 28, 1962, he hauled the scope to the parking area atop Mount Pinos
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CELESTRON
The telescope that was most influential in proving fledgling Celestron’s viability as a company was the 10-inch SchmidtCassegrain shown here with Johnson. In the late ’60s, it cost about $2,000 when outfitted with basic accessories.
CELESTRON
for its public debut at one of the Los Angeles Astronomical Society’s star parties. It made a big impression among the group’s advanced amateurs who examined it in detail. The telescope was so noteworthy that it became the cover story of this magazine’s March 1963 issue. But it was another S&T article that proved especially influential in Celestron’s history. As Johnson was nearing the completion of his 18¾-inch scope, Donald Willey published a seminal analysis of Cassegrain telescopes in the April 1962 issue. Johnson was intrigued by the excellent off-axis optical performance of the Schmidt-Cassegrain design. Based on his experience building the 18¾-inch scope (some of the work involved other Valor employees) and a plan to use optics made to order by Perkin-Elmer Corporation, Johnson took the bold step of advertising a 20-inch multipurpose Schmidt-Cassegrain telescope called the Celestronic 20 in S&T’s January 1964 issue. The Astro-Optical Division name quickly morphed to Celestron Pacific, a division of Valor. By December Valor was dropped, and Celestron’s ad introduced pictures of 4-, 6-, 10-, and 22-inch Schmidt-Cassegrain telescopes as well as mention of a 36-inch. A 16-inch entered the product line in early 1967. But most of Celestron’s sales were for the 10-inch, which cost about $2,000 when outfitted with a few basic accessories. Despite his initial arrangement with Perkin-Elmer, Johnson experimented with making his own SchmidtCassegrain optics. From the outset, he and his colleagues were able to produce them at a pace needed to meet orders. A breakthrough came early on when Johnson blended known technologies with his own experience and techniques to create a method for effectively mass producing the telescopes’ optically complex corrector plates. For this and other contributions to optics, Johnson was later
Made affordable with mass-production techniques (inset), the “classic” 8-, 5-, and 14-inch Celestrons introduced in 1970, 1971, and 1972, respectively, altered the course of amateur astronomy in the decade that followed. By 1979 the product line included binoculars, Schmidt cameras, and many photographic accessories.
awarded the Optical Society of America’s prestigious David Richardson Medal, one of only a few non-Ph.D. optical engineers to ever receive the honor.
Birth of the “Classic” It was a somewhat ironic incident that ultimately established Celestron as a powerhouse in the world of amateur telescopes. A minor economic recession in the late ’60s drastically reduced orders for Celestron’s bread-and-butter 10-inch telescope. Johnson and his colleagues speculated that there would, however, be a market for a quality 8inch portable Schmidt-Cassegrain costing around $1,000. Johnson returned to the drafting table, and what emerged was the $850 “classic C8,” first advertised in S&T’s June 1970 issue. With a radically new orange and tan motif, the C8 was an overnight hit. Sales took off. The Celestron 5 and Celestron 14 (the latter billed as “the world’s largest one-man-portable astronomical observatory telescope”) followed in 1971 and 1972, respectively. In January 1972 the company’s advertising moved to the back cover of this magazine, replacing the venerable Unitron refractor ads that had been there for nearly 20 years. These new ads did more than promote telescopes. For the first time a company devoted major advertising space not only to pictures of its telescopes, but also to pictures taken with its telescopes. Celestron had always touted its scopes’ photographic capabilities, but the monthly parade of colorful planet and deep-sky images was a powerful incentive for prospective buyers. It’s safe to say that the exponential growth of amateur astrophotography during the ’70s was partly due to Celestron. The company’s expanding line of accessories also helped advance astrophotography. It included everySk yandTelescope.com June 2010 37
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Celestron’s Golden Anniversary
thing from simple camera adapters to drive correctors and exotic equipment such as “cold cameras” that made exposures with film frozen at dry-ice temperatures. Furthermore, the popularity of Celestron telescopes spawned a cottage industry of independent businesses making all kinds of accessories. Some were basement tinkerers who came and went quickly, but others grew to become major manufacturers. By the close of the ’70s, Celestron’s product line boasted Schmidt- and Maksutov-Cassegrain telescopes, spotting scopes, telephoto lenses, Schmidt cameras, binoculars, and scores of accessories.
Ups and Downs As a business, Celestron has had its ups and downs. Johnson sold the company to a Swiss firm in 1980, which weathered the boom-and-bust period that pummeled the telescope industry during the apparition of Comet Halley in 1985–86. Celestron changed hands again in 1998 when it was purchased by Tasco, a well-known maker of low-end telescopes, which itself had been acquired by new owners a few years earlier. But Tasco ended up filing a variant of bankruptcy in 2002, and Celestron was literally within hours of a court-ordered liquidation when a small group of dedicated employees stepped in to rescue the business. Today Celestron is owned by a division of Synta Optical Technologies, the Asian-based mega-manufacturer of astronomical telescopes, and is again enjoying a period of stability and growth.
Celestron’s ads were novel at the time for having pictures of its telescopes playing second fiddle to the photography done through them. Many people feel that the explosive growth of astrophotography in the ’70s was due in part to Celestron’s ads.
CELESTRON
Less than a year after its public debut in January 1964, Celestron’s advertising showed this 22-inch Schmidt-Cassegrain telescope (the largest model produced) pictured with Johnson.
Celestron’s multitude of telescope innovations during the past half century are far too numerous to list here. But for those who want to learn more, there are several worthwhile resources. Celestron’s special 50th Anniversary website (www.celestron.com/50) includes an interactive timeline and, of special note, a video documentary, which is being released in stages throughout the rest of this year. It features many historic images as well as on-camera commentary from Johnson and other long-time employees. Another fascinating resource is Robert Piekiel’s CDROM book Celestron — The Early Years ($39.95, direct from the author at PO Box 64, Marcellus, NY 13108; piekielrl@ yahoo.com). Piekiel is an avid collector of vintage Celestron telescopes, and while his 1,800-page e-book places special emphasis on the early models, it is a rich source of company history, including transcripts of interviews with many pivotal employees past and present. From its launch as a manufacturer of specialty telescopes for institutions and advanced amateurs, to the introduction of the legendary C8, to today’s product line with equipment for every level of amateur astronomer, Celestron has remained true to Johnson’s vision of crafting quality astronomical telescopes at affordable prices. The company has left an indelible mark on the astronomical community that will remain long into the future. ✦ S&T senior editor and equipment junkie Dennis di Cicco has been writing about the telescope industry for decades.
38 June 2010 sky & telescope
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Fred Schaaf Northern Hemisphere’s Sky
Sky of Wonders Eleven stars and planets shine at 1st magnitude or brighter on June evenings.
Sunlight filtering through clouds or mountains beyond the horizon create crepuscular rays after sunset.
night long but all year long. This monotonous, wasteful glow hides beautiful and richly meaningful sky wonders. In contrast, all natural twilights are different, and each is a canvas for ever-changing glows and colors. The sky at the Arcturus hour. Even if twilight or light pollution limits how many stars you can see at the Arcturus Hour, the sky will be fascinating. You can see four of the five 1st-magnitude stars that shine in the zodiac near the ecliptic: Antares, Spica, Regulus, and Pollux (setting beside Castor, which is almost 1st magnitude). And June evenings in 2010 are further enriched by three bright planets, as our all-sky map shows. Blazing Venus is not far from Castor and Pollux, Mars is near Regulus, and Saturn burns about halfway between Mars and Spica. Four other stars of 1st magnitude or brighter are visible at the Arcturus Hour: Arcturus itself and all three stars of the ascending Summer Triangle: Vega, Deneb, and Altair — though Altair is still fairly low in the east. And unless your sky is mighty bright, you should see the mostly 2nd-magnitude stars of the Big Dipper, very high in the northwest and standing upright on its bowl. ✦ Fred Schaaf welcomes your comments at
[email protected].
S&T: TONY FLANDERS
shows that the 15h line of right ascension is on the sky’s meridian (the line from north to south). The most prominent object near the meridian at this time is the zeromagnitude star Arcturus, so we will call the sky scene on our map the Arcturus Hour. Night in short supply. The Arcturus Hour occurs around midnight (daylight-saving time) in late May, 11 p.m. in early June, and 10 p.m. in late June. But because the nights are so short, the sky over the northern half of the U.S. isn’t fully dark in late June until after 10 p.m. If you live north of latitude 50° N (most of Canada and Northern Europe), the sky never grows fully dark in June; there’s just a long period of twilight from sunset to sunrise. Natural versus artificial twilight. So night is in short supply at middle and higher latitudes in the month of the summer solstice. But that’s not altogether a bad thing, because long summer twilights make it more likely that you’ll see some amazing sky phenomena. Crepuscular rays (see the photo above right) are most spectacular after sunset. On many clear evenings, the Belt of Venus, shown below, forms a pink arch bordering Earth’s shadow in the east 5 minutes after the Sun has set in the west. And magnificent noctilucent clouds, which catch sunlight long after sunset from their vantage point some 50 miles above the ground, are most likely to form in summer. Unfortunately, night is in short supply in a very different way — one with no consolation — in many parts of the world. I’m talking about areas where light pollution bathes the sky in perpetual unnatural twilight not just all
TAMAS LADANYI
A look at our all-sky map on page 44
40 June 2010 sky & telescope
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June 2010
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June June2010 2010
Sky at a Glance 1
MOON PHASES SUN
MON
TUE
WED
3 EVENING: Mars is less than 2° right
THU
FRI
of Regulus.
SAT
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LAST-QUARTER MOON (6:13 p.m. EDT).
6
DAWN: Jupiter and Uranus are 6° or 7° lower right of the Moon.
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EVENING: Mars is closest to Regulus (about 50′ apart) as shown on page 48.
8
DAWN: Uranus is just 26′ above and slightly left of Jupiter. At magnitude 5.9, Uranus is slightly fainter than Jupiter’s Galilean satellites, and readily visible in binoculars. The planets are within 1° of each other for the first half of June, but this is their closest approach.
10
DAWN: Mercury should be visible in binoculars very low in the east a half hour before sunrise, roughly 9° below and slightly left of the thin crescent Moon (in North America).
11
DAWN: A very thin crescent Moon may be visible very low in the east a half hour before sunrise about 6° to Mercury’s left.
PLANET VISIBILITY ◀ SUNSET
MIDNIGHT
Venus
W
Mars
SW
W E
SW
E
NW
Jupiter Saturn
SUNRISE ▶
Visible June 1 through June 10
Mercury
PREDAWN: Ceres, the biggest asteroid, is passing through the southern part of Messier 8, the Lagoon Nebula; see page 62.
SE
EVENING: Venus, Pollux, and Castor form a straight, nearly horizontal line just over 10° long, as shown on page 49.
W
PLANET VISIBILITY SHOWN FOR LATITUDE 40o NORTH AT MID-MONTH.
©ISTOCKPHOTO / ALOHASPIRIT
12
NEW MOON (7:15 a.m. EDT).
14
EVENING: Venus is 4° or 5° above the thin crescent Moon.
16 EVENING: Mars and Regulus form a flattened, tilted triangle with the Moon.
18
EVENING: Saturn shines about 9° above the Moon. ALL NIGHT: Ceres is at opposition, opposite the Sun in the sky and shining at its brightest for 2010. See page 62.
19
FIRST-QUARTER MOON (12:29 a.m. EDT).
19, 20 EVENING: Venus is less than 1° from the center of Messier 44, the Beehive Cluster. Use binoculars or a small telescope.
21 THE LONGEST DAY of the year in the Northern Hemisphere. Summer begins at the solstice, 7:28 a.m. EDT.
26
In the arctic, the Sun never sets during June. In the North Temperate Zone, the Sun describes a shallow arc beneath the northern horizon, causing long twilights and short periods of total darkness.
worldmags & avaxhome
FULL MOON (7:30 a.m. EDT). A partial lunar eclipse is visible from western North America during dawn, as well as from the Pacific and other surrounding lands; see page 61.
Sk yandTelescope.com June 2010 43
Facing North
Northern Hemisphere Sky Chart
3h Double Cluster
+60n
6h
B
AU
RI G
0h
A
A
CAME
LOPA
R
E
DALIS
CAS
D
PEI SIO G
A
c Fa
B
in
g L +80n
URSA MINOR
82
M
A
B
G A
ca
Spi
CO
in U
Moon2 June 2
P
G
U
S G D
B
A
S
12h C
B
J M
RV
C
C T I P L I E C
E
L
a
B
A
n oo 18 M ne Ju
G
O
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M
SC T A 4 M6 OR 2 PI US
M6
M
an
G
20 8
M7
s
G
LEO
Elt
B
S
are
rn
O
M M
18h
Ant
tu
C
21
44 June 2010 sky & telescope
A
D
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Sa
H
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H
M
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M
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1 2 3 Star 4 magnitudes
C BER OMA ENIC ES
A
B
Z
17
M 25
M M
0
I R
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U E Q
B
N
M1
Denebola
A
B
CANES VENATICI M3
Z
R
M51
H
Z
an A
ES K
S
LIBRA
Moon June 25
B
g r Bi pe ip D
E
r iza or M Alc &
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A
D
ub
UL
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M13
Z E
RC
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UM
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SE
0n
V
U
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6
M1
UT
c Fa
S
Arcturus
M5
M
B
Little Dipper H
P
HE A
A
SC
M I U 10 C H
G
A
M
B
Th
T
A A
G
S EN ) RP DA SE AU (C
H
A
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M92
Vega
E
Q
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M1
P
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R
LYRA
M57
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IU
Polaris
Z
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CULA
G
A
g
TA R
E
B
O
O LE OR N MI
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X
R
E
CY G NU S
B
VULPE
Altair H
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IT
81
E
G
No C r t Cr hern os s
SAGITTA
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BOÖTES
A
A
N
C
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Den eb
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M2 9
E
M27
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G Q
SA
B
M
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70
Y
A
M3 9
E
Facing East
Zenith
L
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M52
N Z
h
21
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LUPUS
–40°
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15h
Facing South worldmags & avaxhome
S RU AU T CEN
N
IN
I
c Fa
in
g
Binocular Highlight:
WHEN
Hunting Dog Messiers
Late April
2 a.m. *
Early May
1 a.m.*
Late May
Midnight*
Early June
11 p.m.*
Late June
Dusk
*Daylight-saving time.
HOW
ER NC A M67 C A
h
HYD RA
Go outside within an hour or so of a time listed above. Hold the map out in front of you and turn it around so the yellow label for the direction you’re facing (such as west or southeast) is at the bottom, right-side up. The curved edge is the horizon, and the stars above it on the map now match the stars in front of you in the sky. The map’s center is the zenith, the point overhead. Example: Hold up the map so that “Facing NW” is at the bottom. About two-thirds of the way from there to the map’s center is the Big Dipper. Go out, face northwest, and look two-thirds of the way from horizontal to straight up. There’s the Dipper! Note: The map is plotted for 40° north latitude (for example, Denver, New York, Madrid). If you’re far south of there, stars in the southern part of the sky will be higher and stars in the north lower. Far north of 40° the reverse is true. The planets are positioned for mid-June.
Canes Venatici may not be a showpiece constellation, but the Hunting Dogs managed to sniff out five Messier objects. We’ve already discussed the globular cluster M3 and the well-known galaxy M51 in earlier columns. That leaves the galaxy trio of M63, M94, and M106. Let’s start our hunt at Cor Caroli, Alpha (α) Canum Venaticorum — a tight, challenging binocular double. The component stars are magnitudes 2.9 and 5.5, but they’re separated by only 19.3″. In my 15×45 image-stabilized binoculars, the companion shows up as a tiny fleck of starlight nearly lost in the glare of its brighter neighbor. M94 lies in the same binocular field as Cor Caroli. I had little trouble picking up this object even in my 10×30 image-stabilized binos. Most of the 8.0-magnitude galaxy’s light is concentrated into its nearly stellar core, but if you use averted vision, you’ll see it’s enveloped in a dim, round halo. Proceeding northeast from Cor Caroli we come to a distinctive asterism of 5th- and 6th-magnitude stars shaped like a sideways L. Nearby is M63, glowing at magnitude 9.0. I can see the galaxy in my 10×30s and even discern that there’s something odd about its nucleus. The extra magnification of my 15×45s makes it clear that the “oddness” results from a 9.3-magnitude foreground star embedded in the galaxy’s elongated glow, giving M63 the appearance of having a double nucleus. Our final stop is M106, the largest and most diff use of this month’s galaxy threesome. Unlike its neighbors, M106 lacks a distinctly stellar core — my 10×30s show it as a mostly evenly illuminated patch that’s elongated in a southeast-northwest orientation. At magnitude 8.7, it’s a little fainter than M94, but its larger size makes it an easier find. ✦ — Gary Seronik
M106
R
A
T
E
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SEXT
ANS
A
ars
Regulus
R
O AT
Facing West
9
A
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M Jun oon e 15
D
M4
4
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x llu Po
B
G
E
A
M
W
r sto Ca
Using the Map
g
SW
C
C ANES VENATI C I
c Fa
in
Galaxy Double star
At SkyandTelescope.com/ skychart, you can create a sky chart that’s customized for any particular date, time, and location.
M63
5°
bino
cular vie
M94
w
B
Variable star Open cluster Diffuse nebula
Cor Caroli
Globular cluster
A
Planetary nebula
Sk yandTelescope.com June 2010 45
worldmags & avaxhome
Planetary Almanac
Sun and Planets, June 2010
Mercury
June
11
June 1
21
30
Declination
Elongation
h
m
+21° 59′
––
h
m
+23° 12′
1
h
2 58.9
m
11 21
Sun
Right Ascension
1
Venus
30 Mercury
1
30
16
16
Jupiter
––
–26.8
31′ 28″
––
1.017
+13° 41′
24° Mo
+0.1
7.3″
50%
0.924
3h 57.6m
+18° 38′
19° Mo
– 0.6
6.0″
71%
1.113
5h 17.9m
5.3″
93%
1.273
+24° 28′
2° Ev
–2.2
5.1″
100%
1.327
h
7 02.1
m
+24° 33′
34° Ev
–3.9
13.0″
81%
1.286
11
7h 53.2m
+22° 55′
36° Ev
– 4.0
13.7″
78%
1.220
21
8h 42.1m
6 43.1
+20° 17′
38° Ev
– 4.0
14.5″
74%
1.150
h
m
+17° 11′
40° Ev
– 4.1
15.4″
71%
1.085
1
h
9 57.4
m
+13° 58′
76° Ev
+1.1
6.0″
90%
1.559
16
10h 27.1m
+10° 56′
70° Ev
+1.2
5.6″
91%
1.680
30
10h 55.8m
9 23.9
+7° 49′
64° Ev
+1.3
5.2″
91%
1.785
h
m
–1° 25′
71° Mo
–2.3
37.9″
99%
5.207
30
h
0 10.7
m
– 0° 14′
96° Mo
–2.5
41.4″
99%
4.765
1
11h 55.4m
+3° 09′
107° Ev
+1.0
18.1″
100%
9.168
30
11h 58.0m
1
Saturn
Uranus
1.014
–1.4
Jupiter
Saturn
––
9° Mo
Mars
16
31′ 33″
+23° 08′
30
FPO
–26.8
m
1
30
Distance
h
Venus 1
Illumination
6 34.7
30
Mars
Diameter
4 34.6
Magnitude
23 58.5
16
+2° 45′
80° Ev
+1.1
17.2″
100%
9.645
h
m
– 0° 34′
84° Mo
+5.8
3.5″
100%
20.169
h
m
0 02.2
Neptune
16
22 03.2
–12° 26′
116° Mo
+7.9
2.3″
100%
29.558
Pluto
16
18h 17.6m
–18° 14′
169° Mo
+14.0
0.1″
100%
30.851
16 The table above gives each object’s right ascension and declination (equinox 2000.0) at 0 h Universal Time on selected dates, and its elongation from the Sun in the morning (Mo) or evening (Ev) sky. Next are the visual magnitude and equatorial diameter. (Saturn’s ring extent is 2.27 times its equatorial diameter.) Last are the percentage of a planet’s disk illuminated by the Sun and the distance from Earth in astronomical units. (Based on the mean Earth–Sun distance, 1 a.u. is 149,597,871 kilometers, or 92,955,807 international miles.) For other dates, see SkyandTelescope.com/almanac.
Uranus Neptune Pluto
10"
2h
4h
+40°
RIGHT
Planet disks at left have south up, to match the view in many telescopes. Blue ticks show the pole tilted Earthward.
0h 22h ASCENSION
+30°
Mercury +20°
Pleiades
Jupiter
–30° –40°
DECLINATION
–10°
–20°
E RI DA NUS
Castor Pollux
Uranus
CETUS
VIRGO
Mars
E Q U AT O R
Neptune AQU ARIU S 2
LIBRA
ECL
Fomalhaut
SAGITTARIUS 2 am
June 25–26
15
Spica
+10° Betelgeuse
Procyon
0°
ORION
18
IC IPT
CORVUS
21
CAPR ICORNU S
4 am
+20° Regulus
Saturn
H Y D R A
CANIS MAJOR
4 pm
2 pm
Sirius
Antares
SC O RPIU S Midnight 10 pm
worldmags & avaxhome
–10°
–20° –30°
8 pm
6 pm
The Sun and planets are positioned for mid-June; the colored arrows show the motion of each during the month. The Moon is plotted for evening dates in the Americas when it’s waxing (right side illuminated) or full, and for morning dates when it’s waning (left side). All dates are in June. “Local time of transit” tells when (in Local Mean Time) objects cross the meridian — that is, when they appear due south and at their highest — at mid-month. Transits occur an hour later on the 1st, and an hour earlier at month’s end.
46 June 2010 sky & telescope
6h
+30°
CAN C ER
Pluto
LOCAL TIME OF TRANSIT 10 am 8 am 6 am
GEMINI
Venus
LEO
Arcturus
OPHIUCHUS
5
8h
10 h
AQUILA
PISCES
Rigel
12h
14 h BOÖTES
HERCULES
PEGASUS
8
0°
16 h
Vega
CYGNUS
ARIES
+10° T A U R U S
18h
20 h
–40°
Jupiter’s Moons
Saturn’s Moons June 16 0h UT
June 1 2
EAST
WEST
June 1
3
2
4
3
5
Ganymede
EAST
WEST
Titan
4
6
5
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6
The Universe in a Mirror
8
7
The Saga of the Hubble Space Telescope and the Visionaries Who Built It
9
8
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Europa
Robert Zimmerman
Tethys
With a new afterword by the author
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25
Callisto Io
24
“Zimmerman vividly describes the building of the telescope, the turf wars among bureaucrats, scientists and congressional staffers, and the trials and tribulations of the Hubble itself once it was launched. . . . [A] page-turner full of human drama.” —Glenn Harlan Reynolds, Wall Street Journal Paper $19.95 978-0-691-14635-5
Dione
Titan Unveiled Saturn’s Mysterious Moon Explored
Rhea
Ralph Lorenz & Jacqueline Mitton
25
With a new afterword by the authors
27
26
28
27
29
28
30
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“Titan Unveiled describes how most of what we once hypothesized about Titan has been proved wrong. The story of how we gained our current knowledge is fascinating; even more intriguing is what remains to be learned.”—Henry Roe, Nature
July 1
30
26
Enceladus
Paper $19.95 978-0-691-14633-1 July
July 1 The wavy lines represent major satellites of Jupiter and Saturn. The central vertical lines represent Jupiter (left) and Saturn and its rings (right). Each gray or black horizontal band is one day, from 0 h (upper edge of band) to 24h UT (GMT). The UT date is given at left. Slide the edge of a piece of paper down to your date and time, and read across to see the satellites’ positions east or west of the planet at that time.
press.princeton.edu
Sk yandTelescope.com June 2010 47
worldmags & avaxhome
Fred Schaaf Sun, Moon, and Planets
A Seven-Planet Month All the major planets are reasonably easy to observe in early June. During evening twilight in June, three planets form a diagonal line in the western sky: Saturn at upper left, Mars in the middle, and bright Venus fairly low on the right. Jupiter and dim Uranus are partway up the southeastern sky at dawn. And early in June, Mercury hovers low in the east before sunrise. A partial eclipse of the Moon on June 26th is visible in its entirety over most of the Pacific Ocean. It’s interrupted by moonset and daybreak across the western two-thirds of North America (see page 60 for details).
DUSK Venus won’t reach greatest elongation from the Sun until August. But for viewers at mid-northern latitudes, June is the month when Venus appears highest right after sunset. This is true because the planet is moving rapidly south relative to the Sun, as shown on the bottom of page 46. Venus, shining at magnitude –4.0, forms a straight line, just over 10° long, with fainter Pollux and Castor on June 11th. On June 19th and 20th Venus is in central Cancer, less than 1° from the center of big Messier 44, the Beehive Star Cluster — a lovely sight for binoculars and for telescopes at low magnification. Mars spends the first dozen evenings of June near 1.4-magnitude Regulus. The planet is only a little brighter than the star, but their proximity intensifies the orangeyellow of Mars and blue-white of Regulus. On June 3rd, Mars is less than 2° right of Regulus in North America’s evening sky. The pair is closest on June 6th, with Mars just 50′ upper-right of the star. Mars is 1° above Regulus on the 7th, and after that Mars moves roughly ½° per day to the star’s upper left.
Mars sets around the middle of the night. In telescopes it’s a nearly featureless dot less than 6″ wide. Saturn reaches quadrature (90° east of the Sun) on June 19th. Saturn dims a trace in June, from magnitude +1.0 to +1.1, because Earth is moving away from it now, as shown on the facing page. But the bigger reason that Saturn is dim is the narrowness of its rings. In late May the rings were tilted 1.7° from edgewise, and now they’re just beginning to open, reaching 2.1° at the end of June. Not until 2024 will the rings appear this thin, and the faint inner moons of Saturn this easy to observe (see last month’s issue, page 61). By month’s end Saturn sets not long after midnight (daylight-saving time). Note
To see what the sky looks like at any given time and date, go to SkyandTelescope.com/skychart.
that Mars and Venus are closing in on Saturn from the lower right. They will catch the ringed planet, just nine days apart, in early August.
L AT E N I G H T Pluto, in Sagittarius, is at opposition to the Sun on June 25th and highest in the south in the middle of the night. Even now, when Pluto is closest to Earth for the year, you will probably need at least an 8inch telescope and quite dark skies to see the 14th-magnitude Kuiper Belt object. For
Dawn, June 5 and 6
June 5 and 6
1 hour before sunrise
Shortly after dark
Moon June 5 Regulus
Moon June 6
Mars
Sickle of LEO
Less than 1o apart! Jupiter
Procyon
Looking East-Southeast
48 June 2010 sky & telescope
worldmags & avaxhome
Looking West
December solstice
ORBIT S OF THE PL ANE T S The curved arrows show each planet’s movement during June. The outer planets don’t change position enough in a month to notice at this scale.
Earth June solstice
FPO Saturn
AFTER MIDNIGHT Neptune, at the border of Capricornus and Aquarius, rises before the middle of the night and is highest at the beginning of morning twilight. Finder charts for the two outermost major planets are available at SkyandTelescope.com/uranusneptune. Jupiter and Uranus, in Pisces, are within 2° of each other throughout June. They rise after midnight (daylight-saving time) and are still fairly low in the east or southeast as the sky starts to grow light. But by mid-June they should be high enough for you to get reasonably crisp telescopic views just as dawn begins to brighten. Even if you can’t resolve Uranus’s 3.5″-wide disk every morning, a telescope may reveal its blue-green hue. Jupiter and Uranus are less than 1° from each other from June 1st through 16th, and less than ½° apart from the
Pluto
6th through 10th. They reach conjunction — their first of three in a six-month span — on June 8th, when Jupiter shines at magnitude –2.3 with 5.9-magnitude Uranus 26′ to its northwest. Uranus is at quadrature (90° west of the Sun) on June 22nd, Jupiter on June 23rd.
DAWN
half of June for observers at mid-northern latitudes, and it brightens from magnitude 0 to –1. But these statistics are misleading. June dawns are long, just like June evening twilights, and the sky is quite bright by the time Mercury rises a few degrees above the eastern horizon. This makes Mercury a fairly tough target unless you use binoculars.
Mercury rises in the dawn a respectable one hour before sunrise during the first
MOON AND SUN
Dusk, June 13 and 14
1 hour after sunset
1 hour after sunset
Castor
GEMINI
Venus Pollux Moon June 14
Castor
GEMINI Moon June 13
Procyon
Looking West-Northwest
Uranus Jupiter Neptune
Dusk, June 11
Pollux
Sept. equinox
Sun
Mars
a finder chart, see next month’s issue or SkyandTelescope.com/pluto.
Venus Straight line
Mercury
Venus
March equinox
Looking West-Northwest
On June 6th in North America, the waning crescent Moon is 6° or 7° upper left of Jupiter before dawn. On June 10th, Mercury should be visible in binoculars 8° or 9° below and slightly left of a thin Moon a half hour before sunrise. At the same time on the 11th, a very thin crescent Moon may be visible about 6° to Mercury’s left. The Moon is waxing again at dusk on June 14th, when it’s 4° or 5° below Venus. After that, the Moon passes below Regulus, Mars, and Saturn on June 16th, 17th, and 18th. The Moon is full on June 26th, when it will be partially eclipsed by Earth’s shadow at dawn for western North America. The Sun arrives at the solstice at 7:28 a.m. EDT on June 21st, beginning summer in the Northern Hemisphere and winter in the Southern Hemisphere. ✦ Sk yandTelescope.com June 2010 49
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Save Your Back Issues
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Saturday Night Banquet Dr. Roger Angel Director of the University of Arizona Mirror Lab
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Charles A. Wood Exploring the Moon
Not Only Angels Have Halos Hunt for elusive dark halo craters. The origin of lunar craters used to be a contro-
exist where gas-rich pockets of magma erupted, violently spewing volcanic ash around them. The Alphonsus dark halo craters themselves are only about two or three kilometers in diameter, making them difficult to observe from Earth. Their halos, however, are typically three times as large and are thus much easier to spot. Another classic dark halo crater is just southeast of Copernicus. When seen with the Sun high overhead, the 5-km-wide bright-rimmed crater Copernicus H is surrounded by a roughly 15-km dark halo, but there are curiously no nearby rilles or other volcanic landforms. Spectral investigations show that this halo is actually pulverized mare basalts. Looking at the larger scene reveals that Copernicus H was formed when an object impacted into bright ray material ejected by Copernicus. So Copernicus H is a different type of dark halo crater — a normal impact crater that excavated deep enough to churn up the underlying dark lavas. Look around Copernicus, and you’ll see more dark halo craters, most so small that the
versial subject. It wasn’t until the 1960s that studies of impact and nuclear-bomb craters on Earth, measurements of lunar crater dimensions, and samples returned by the Apollo missions provided compelling evidence for impacts. We now know that nearly all lunar craters, from 1,000-kilometer-wide basins to microscopic zap pits, resulted from the hypervelocity collisions of particles, boulders, and mountain-sized asteroids with the Moon. But some craters are clearly volcanic, such as lava tubes with collapsed roofs, and pits on the summits of volcanic domes. There are also a small number of others whose origin seems uncertain. In this category are dark halo craters, which have two different origins. The most famous dark halo craters are those on the floor of Alphonsus. These craters have long been thought (correctly) to be small volcanoes, because most lie on narrow rilles. Such rilles are surface cracks produced by vertical sheets of magma that pushed upward. Dark halo craters
HOWARD ESKILDSEN / TIPPY D’AURIA
WES HIGGINS
Theophilus
Above: The crater pits surrounded by dark halos along the inner rim of Alphonsus are evidence of volcanic activity on the Moon, due to gas-rich pockets of magma erupting and spewing debris across the surrounding area. Left: The dark halo craters near Theophilus are the result of a different process. Younger impacts penetrated the bright ejecta blanket deposited by an older event, dispersing dark mare lavas previously hidden from view.
Sk yandTelescope.com June 2010 51
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Exploring the Moon
Astro-Tech is more than just great scope values . . . Sure, Astro -Tech is known for giving you scopes with “more performance for AT106LE less money,” $1495 like the big including Astro-Tech 10” mounting rings and and 12” Ritcheyhard case Chrétien astrographs that sell for thousands less than competitive R-Cs. Then there are the refractors, like the 106mm AT106LE FPL-53 ED triplet refractor, above. It is priced a full $800 less than a competitor’s similarlyequipped 105mm FPL-53 triplet. But Astro -Tech also makes “more performance for less money” eyepieces, like the premium 2” Titan Type II 68° field 30mm to 40mm eyepieces, left. With twist-up eyecups and an ED element in their six-lens systems, they sell for only $159.95. And then there are the unique 1.25” Paradigm 60° field 5mm to 25mm eyepieces, right. They have twist-up eyecups and dual ED elements in their six-lens/four group optical system for exceptionally flat fields that are free from spurious color. They are only $60 each.
impact craters themselves are invisible from Earth. The fact that dark halo craters were formed by two completely different mechanisms creates an observing challenge. Can you identify the origin of each dark halo crater you happen to see? Let’s look at a few and fi nd out. Start in northern Mare Nectaris. Two lie to the southeast of Theophilus. To correctly infer their origins, you’ll need to look for other nearby volcanic landforms such as rilles and domes, or a thin layer of bright ejecta covering mare lavas. If you observe this area under low lighting you won’t find any volcanic features, but the high Sun view confirms that the dark haloed craters sit on a broad apron of bright ejecta from Theophilus. Two more dark halos occur on the floor of Atlas. This area is near the northeast limb, so foreshortening makes it difficult to see its floor. A broad dark patch on the
southern rim area and a smaller deposit occurs near the north wall. There are irregular shaped craters at the center of these halos and a family of rilles passes near them, providing evidence that these are indeed little volcanos. To start your own search, observe far from the terminator to maximize the contrast between normal bright terrain and dark halos. Most dark halo craters are small, so use magnifications of roughly 150 to 200× to clearly detect them. Avoid searching the lunar highlands, because both types of dark halo craters ultimately rely on volcanic materials, and most highland areas have little volcanism. Once you find a dark halo crater, look for evidence to decide if it is of volcanic or impact origin. Good hunting! ✦ To get a daily lunar fix, visit contributing editor Charles Wood’s Lunar Photo of the Day website: lpod.wikispaces.com.
The Moon • June 2010 Highlighted feature
Size (miles)
Description
A Alphonsus
71 miles
Large crater with floor rilles and dark areas
B Theophilus
61 miles
Large crater with irregular central peak
The newest Astro-Tech eyepieces are the 1.25” 8mm to 27mm Flat Fields, left, with twist-up eyecups. Their five-element optics give you 53° to 65° fields with pinpoint stars from edge to edge. With more focal lengths available, and for only $79.95, they give you a significant edge on the competition.
C Atlas
53 miles
Large crater with floor rilles and dark areas
With six eyepiece series starting with 1.25” Plössls at only $29.95 (and more to come), Astro-Tech does indeed give you “more performance for less money.”
Distances
ASTRO-TECH from Astronomy Technologies
20
Phases Last quarter
June 4, 22:13 UT
New Moon
June 12, 11:15 UT
First quarter
June 19, 4:29 UT
Full Moon
June 26, 11:30 UT
Apogee 251,199 miles
June 3, 17h UT diam. 29′ 26″
Perigee 227,379 miles
June 15, 15h UT diam. 32′ 39″
C
26
B
A
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[email protected] Prices as of 3/1/10 but subject to change. All prices plus freight.
Librations Cabeus (crater)
June 3
Vallis Baade
June 7
Mare Humboldtianum
June 20
Mare Marginis
June 26
A N TO N
7
ÍN R
ÜK
L
June 3 For key dates, yellow dots indicate what part of the Moon’s limb is tipped the most toward Earth by libration under favorable illumination.
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S&T: DENNIS DI CICCO
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S & T Test Report
Dennis di Cicco
Atik’s 314L CCD Camera
ALL PHOTOGRAPHS BY S&T: DENNIS DI CICCO & SEAN WALKER
This exceptionally easy-to-use camera produces first-rate images.
There was very little, at least on paper, preparing me in advance for the experiences I’d have testing Atik’s new 314L CCD camera. There are no written rules for classifying astronomical cameras, but price, chip size, or pixel count (alone or in some combination) usually defines a camera as being targeted for beginning, intermediate, or advanced users. As such, it wasn’t obvious to me which category the 314L belonged in, except that it wasn’t aimed at the advanced-imaging crowd. With an active imaging area measuring about 9 by 6.7 millimeters, the 314L’s chip is rather modest by today’s standards. Nevertheless, it’s still larger than the legendary Kodak KAF-400 chip that took the amateur community
Atik 314L CCD Camera U.S. price: $1,643 Atik-USA, 5108 Pegasus Court, Suite M, Frederick, MD 21704 877-284-5226; www.atik-usa.com
Above: Attached to a Tele Vue-NP101 (4-inch) f/5.4 refractor, the Atik 314L covers a 56′ by 42′ field of view, which is large enough to record the well-known galaxy pair M81 and M82 in Ursa Major. This author created this view by combining 25-minutes of exposure through red, green, and blue filters with a 45-minute exposure made with no filter.
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by storm 15 years ago and arguably drove the final nail into the coffin of film’s dominance for astrophotography. Furthermore, the Sony ICX-285AL chip in the 314L has 1.44 megapixels — nearly four times more than the KAF400. This means the 314L covers almost four times more sky than the KAF-400 for any given resolution. At a resolution of 2 arcseconds per pixel — an image scale suitable for deep-sky shooting — the 314L covers a 46′ × 35′ field of view. Very respectable. And that image scale requires an effective focal length of just 665 mm, making the camera well matched for use with many popular refractors and small reflectors. For this review, Atik-USA lent us the 314L and EFW-U motorized filter wheel, which holds five standard 1¼-inch filters. When ordered with the camera, the filter wheel costs $251, just half of its $503 stand-alone price. Both come with all necessary cables, including 12-volt DC power cords with “cigarette” style plugs. I powered both units from the same 3-ampere AC adapter. Both also require USB 2.0 connections to your computer. All the optical fittings on the camera and filter wheel use standard Tthreads, giving you a wide range of options for attaching the camera to telescopes. The camera is supplied with a 1¼-inch nosepiece, which I used for all my tests. My first surprise came as I pulled the 314L and fi lter wheel from their respective boxes. Both are handsome, very-well-made pieces of equipment that are smaller and lighter than I expected. The camera weighs only 14 ounces (0.4 kg), and with the fully loaded fi lter wheel tips the scales at about 27 ounces. As such, it won’t stress your telescope’s focuser. I had no problems using the setup with a relatively lightweight Crayford-style focuser typical of those found on low-cost refractors. The software was an even bigger surprise, but for reasons you might not expect. The camera comes with an image-acquisition program called Artemis Capture. It controls the camera and filter wheel. Also supplied are software “plug-ins” that let you use the setup with the popular image-capture and processing programs MaxIm DL and AstroArt, which you have to purchase on your own. Although I’m an experienced MaxIm user, as well as being someone who hates learning new software, I stuck with Artemis Capture, since it’s what first-time CCD owners will likely be starting with. What a nice experience it turned out to be. The program is very simple with only a few WHAT WE LIKE: pull-down menus. FurtherExcellent performance more, all the main functions Very easy to operate are available by clicking icons Very well made on the menu bar. I don’t have room to WHAT WE DON’T LIKE: describe all of Artemis CapImage-processing ture’s details here, but, in software not included my opinion, the program’s
The simplicity of Artemis Capture is a huge plus for people new to working with an astronomical CCD camera, since it reduces the 314L’s learning curve to minutes instead of hours or days. In addition to a 30-second exposure of the Orion Nebula made with an 8-inch f/8 reflector, several dialog boxes are shown for the purpose of illustration. The “Sequencer” dialog makes it particularly easy to set up an automated series of exposures.
greatest strength lies in its lack of features. In less than 45 minutes I had loaded the software, connected the camera and fi lter wheel, virtually mastered all of the program’s functions, and acquired a handful of images of paint cans on my basement shelf (I began my learning curve with a camera lens attached to the 314L). Artemis Capture is a very easy program to learn, and that should be a huge benefit for people who have been intimidated by astronomical CCD cameras in the past. I liked the program so much that I used it exclusively for the images appearing with this review. I really liked its
Only 4 inches (10 cm) in diameter and weighing just 27 ounces (0.77 kg), the Atik 314L and motorized filter wheel place a very modest load on a telescope’s focuser, making it suitable for may popular low-cost refractors and reflectors.
Sk yandTelescope.com June 2010 55
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S&T Test Report
One of the author’s first nighttime shots with the 314L was this “keeper” of the Orion Nebula made with 3-minute exposures through red, green, and blue filters with the TVNP101 refractor.
simple procedure for setting up an automatic sequence of images (something you do with a few mouse clicks) using the camera alone or in combination with the fi lter wheel. Don’t get me wrong; Artemis Capture isn’t perfect, nor is it the only program you’ll need. For example, you can’t use it to process your images. Indeed, Artemis Capture only displays the image you’ve just taken. You can adjust the appearance of the image on your computer’s display without affecting the raw data, but once an image is replaced with a newly captured one, you can’t use the program to
view a previous or saved image. So you’ll also need an image-processing program that can deal with the camera’s FITS files (standard format for astronomical images). My S&T colleague Sean Walker suggests DeepSkyStacker (http://deepskystacker.free.fr). It’s a capable image-processing program that’s available as freeware. And, of course, there are many good commercial programs. Artemis Capture’s simplicity proved its worth under the stars. I usually write off my first few nights testing cameras to a learning process. But working with Artemis
As mentioned in the accompanying text, the 314L’s exceptionally “clean” raw images produce acceptable pictures without the extra effort of first calibrating them. The author assembled these views of the spiral galaxy M101 in Ursa Major from the same set of seven 5-minute exposures he took with the TV-NP101. The view at left is a stack of raw frames, while the better image at right used dark and flat-field frames for calibrating the raw files.
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Capture and the 314L went so smoothly that I came away from the first evening with several “keeper” images, including the Orion Nebula shot on the facing page. My first night out also provided another unexpected experience. Anyone who has watched as raw images from an astronomical camera are downloaded to a computer screen knows that they look, well, raw. Most of them are speckled with “hot” pixels that must be removed during image processing. Not so with the 314L. Its raw images are remarkably clean. They’re so clean that you can achieve very acceptable results without having to go through the image-calibration processes that involve dark and flat-field frames. For example, compare my views on the facing page of the spiral galaxy M101. Both pictures were made from stacks of the same exposures; one with and one without first calibrating the raw frames. This has interesting benefits for the beginner who has previously been worried about the mysterious and complex-sounding image-calibration procedures. Here again, don’t get me wrong. I’m not advocating that people stop calibrating 314L images, since you’ll always get the best results when you do. But if you’re just starting out, you can probably create exciting pictures working with raw frames. It’s another important reason for considering the 314L if you’ve been reluctant to try imaging with astronomical cameras because of their perceived complexities. But the 314L is not just a beginner’s camera. With regulated, fan-assisted thermoelectric cooling (I constantly ran the camera at 25° C below ambient air temperature), the camera is tailor made for advanced-imaging techniques, not to mention real scientific work. The Sony CCD is also quite sensitive, with estimates of its quantum efficiency being about 65% (Sony doesn’t release data on the chip’s efficiency). For readers who want to delve more into the camera’s technical specifications, as well as see detailed bench tests, I highly recommend the article by CCD expert Craig Stark that’s available on the Atik website. It was originally published in the on-line magazine AstroPhoto Insight. In the digital age, if you want to produce great astrophotos, you have to spend time sitting in front of a computer processing images, regardless of how, or with what kind of camera, you captured them. Working with an astronomical camera also means that you’ll be sitting in front of a computer while you’re capturing the images. But the 314L makes that experience very pleasant, even for first-timer CCD shooters. And the 314L is also a camera that will let you play in the big leagues, if you want to advance to more sophisticated imaging techniques. Its imaging performance is on par with other astronomical cameras costing a lot more. ✦ S&T senior editor Dennis di Cicco spent more than five years doing astrophotography with a KAF-400 CCD before moving on to a more advanced camera.
Top: The sensitivity of the the Atik 314L’s Sony ICX-285AL CCD chip is evident in this view of the Whirlpool Galaxy, M51, made with a stack of nine 5-minute exposures taken through an AstroTech 8-inch f/8 Ritchey-Chrétien reflector. Middle: The 314L is also a very capable camera for lunar and planetary imaging. This 0.004-second exposure of the Moon was made at f/5.4 with the TV-NP101 refractor. Bottom: This view of M51 was made with the TV-NP101 and 25-minutes of exposure through red, green, and blue filters added to almost 90 minutes of unfiltered data.
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New Product Showcase
TASTY TOPICS Jean Meeus, Belgium’s patriarch of astronomical computations, has completed his latest exploration of the celestial clockwork, Mathematical Astronomy Morsels V ($29.95). Following in the footsteps of the preceding four volumes, the new book probes a gamut of fascinating astronomical events, from solar and lunar eclipses, to asteroid transits of Jupiter, Saturn, Uranus, and Neptune. Using tables, graphs, diagrams, and hundreds of pages of highly readable text, Meeus sheds light on some extraordinary astronomical happenings past, present, and future. Hundreds of celestial events are chronicled in Morsels V, and if you own one or all of the previous volumes, the cumulative index in the newest book will be of special value. 390 pages, ISBN 978-0-943396-92-7. Willmann-Bell P.O. Box 35025, Richmond, VA 23235; 804-320-7016; www.willbell.com
WILLMANN-BELL
◀
GO TO MAK Celestron introduces the NexStar 127SLT ($549.95), a 5-inch Maksutov-Cassegrain telescope combined with the company’s esteemed NexStar computerized mount. The 5-inch, f/11.8 tube assembly features multi-coated optics with enough aperture to reveal detail in Jupiter’s cloud bands, and resolve stars in globular clusters. The NexStar alt-azimuth Go To mount comes with an adjustable stainless-steel tripod, and a quick-release dovetail tube attachment, allowing you to set up for observing in a matter of minutes. The NexStar 127SLT controller includes a database of more than 4,000 celestial objects, and features Celestron’s patented SkyAlign three-object alignment. The package comes with a 1¼-inch 90° star diagonal, a unit-power red-dot finder, and 25- and 9-mm eyepieces. It requires eight AA batteries (not included). Celestron 2835 Columbia St., Torrance, CA 90503 310-328-9560; www.celestron.com ▾
CAMERA CONTROL PLUS Greg Fisch, known from the early days of computerized telescope control for his groundbreaking Epoch 2000 planetarium program, introduces Fisch ImageLab ($249), an easy-to-use camera control and image-processing package for Windows. The program allows you to operate most popular CCD or digital SLR cameras (with the appropriate cables), and an autoguider simultaneously to record high-quality astrophotos with ease. Fisch ImageLab will automatically calibrate, rotate, and stack your images even when imaging in alt-azimuth configuration. Additionally, the software includes a full suite of post-processing tools, including RGB combine, digital development, Gaussian blur, deconvolution, unsharp mask, and wavelet sharpening routines. Fisch ImageLab is compatible with Microsoft Windows XP, Vista, and Windows 7 operating systems. Available from Explore Scientific 949-916-2418; www.explorescientific.com ▴
New Product Showcase is a reader service featuring innovative equipment and software of interest to amateur astronomers. The descriptions are based largely on information supplied by the manufacturers or distributors. Sky & Telescope assumes no responsibility for the accuracy of vendors’ statements. For further information, contact the manufacturer or distributor. Announcements should be sent to
[email protected]. Not all announcements can be listed. CELESTRON
58 June 2010 sky & telescope
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Louis Moinet www.lmtime.com COSMIC TIMEPIECES With a degree of measured understatement, renowned luxury watchmaker Louis Moinet calls its Meteoris offering a “pièce de résistance” for the ultimate watch collector. The four one-of-a-kind tourbillon watches have faces inlaid with slices of rare meteorites, including authenticated specimens originating from the Moon and Mars and another estimated to be more than 4.5 billion years old. Complementing the four-timepiece collection is an equally intriguing mechanical orrery, noteworthy for showing nine planets from Mercury to Pluto and its ability to compress a year’s worth of planetary motion into 37 seconds. Fashioned with 18-carat white and rose gold and embellished with more than 9 carats of Top Wesselton diamonds, the collection is priced at $4.7 million (we didn’t ask if shipping is extra).
LOUIS MOINET (2)
◀▴
ED FOCAL-REDUCERS Orion Telescopes & Binoculars has introduced three focal reducers ($199 each) that transform its ED apochromatic refractors into faster astrographs. Each 0.85× focal reducer/field flattener features a two-element design with one element made of extra-low-dispersion glass. Individually matched to Orion’s 80mm ED, 100mm ED, and 120mm ED apochromatic refractors, they thread directly onto the telescope’s focuser, yielding focal ratios of f/6.3, f/7.65, and f/6.38, respectively. They are designed to illuminate detectors as large as 24-by-36 mm, and are threaded for standard T-rings on the camera side of the reducer. Orion Telescopes & Binoculars 89 Hangar Way, Watsonville, CA 95076; 800-447-1001; www.oriontelescopes.com ▶
ORION TELESCOPES & BINOCULARS
THE BEST TARGETS Astro-imagers looking for interesting targets will enjoy The 100 Best Astrophotography Targets: A Monthly Guide for CCD Imaging with Amateur Telescopes by Ruben Kier ($34.95). Kier draws on his technical expertise and wide experience as a visual observer and astrophotographer to help you choose targets based on your equipment. Lavishly illustrated with the author’s color images, the book will help you get the most out of any clear, moonless night throughout the year. Also included are chapters on selecting equipment, and basic imageprocessing techniques to get you started. 360 pages, ISBN978-1-4419-0602-1. Springer 233 Spring St., New York, NY 10013; 212-460-1500; www.springer.com Sk yandTelescope.com June 2010 59 ◀
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Alan MacRobert Celestial Calendar
A Comet in the June Dawn Bring a telescope to catch this early-morning quarry low in the east to northeast. 5h
6h
4h
H
3h
2h
1h
G
25
M76
21
T
B
P at h
N
E
H
Q
of Co
met
McN
Z
AURIGA
A
17
A
Capella
+50°
+45°
D
aug
ANDROMEDA
ht
K
N
E
M38
M31
13
B
+40°
G
9
M
M34
5
B +35°
M36
R
B
Star magnitudes 1 2 3 4 5 6 7
Jun 1
PERSEUS
I
B G
Z
O
TRI
M33
+30°
A
Running just south of the main stars of Andromeda, then cutting across Perseus, this year’s springtime comet may be a tricky catch in binoculars or a small telescope just before dawn. Use this map to locate its exact position in your field of view. The tick marks are for 0:00 Universal Time on the dates indicated; dawn on the same date in North America comes nearly a half day later. The comet symbols are exaggerated in size and brightness. Their tails are oriented away from the Sun.
It’s unusual for us to see a comet at its best. Most comets are brightest when they’re nearest to the Sun, just when they’re likeliest to be hidden in the Sun’s glare or below the sunrise or sunset horizon. Comet C/2009 R1 (McNaught) is, alas, no exception. But it should be visible in small telescopes and possibly binoculars in the Northern Hemisphere’s pre-dawn sky for at least part of June, during its run-up in brightness. This particular Comet McNaught is one of 54 named so far for Robert H. McNaught of Australia’s Siding Spring Observatory. He works in the Siding Spring Survey, funded by NASA to record large swaths of sky to find potentially hazardous near-Earth objects. The survey also turns up many other moving things. McNaught found this comet (which will never come near Earth) at 17th magnitude on an image taken last September 9th. Prediscovery images quickly established its orbit.
Most comets remain too faint for amateur scopes (149 new ones were discovered last year, 6 from the ground by amateurs), but C/2009 R1 should rise out of the ordinary.
Comet Timetable Springtime finds Comet McNaught moving north in its highly inclined orbit, which is tilted 77° to the plane of the ecliptic. In mid-May the comet is still only about 10th magnitude, cutting the southeastern corner of the Great Square of Pegasus and rising about an hour before the start of astronomical twilight for mid-northern observers. It will be low in the east when dawn begins to brighten, and that unfortunately sets the pattern for this apparition. May 31st finds McNaught, now hopefully 8th magnitude, passing 2½° southeast of 2nd-magnitude Beta Andromedae. At the beginning of astronomical twilight it’s a respectable 20° up as seen by observers at 40° north lati-
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tude, but the waning gibbous Moon will brighten the sky. On the morning of June 5th the comet skims just north of the large, loose open cluster NGC 752. On June 6th and 7th it’s within about 2° of the 2nd-magnitude double star Gamma Andromedae. The Moon is much thinner then, but also closer to the comet. Mid-June is when Comet McNaught should be most interesting, offering the best compromise between increasing brightness and decreasing altitude at the start of dawn. Moreover, the sky will be free of moonlight. The helpful conjunctions continue as the comet passes about 1° north of the open cluster M34 in Perseus on the morning of June 10th, and 3° south of 1.8-magnitude Mirfak (Alpha Persei) on the 13th and 14th. It’s still about 15° high in the northeast as the sky starts to grow light on June 15th, but it appears roughly 1° lower every day after that. It passes zero-magnitude Capella on the 21st, and it’s
very low by the 24th, when it passes 2nd-magnitude Beta Aurigae. By now Comet McNaught may be as bright as 6th magnitude, but moonlight is returning. The comet will be lost to view by June’s end — just before it reaches perihelion on July 2nd, 0.405 astronomical unit from the Sun. It remains far from Earth throughout this apparition, never venturing closer than 1.135 a.u. (in mid-June). After perihelion it will fade rapidly as it heads to the far-southern sky. The comet is approaching on a slightly hyperbolic orbit, which means that it’s making its first trip in from the Oort Cloud. So how bright it will become is even less certain than usual. Will it flare unexpectedly or perhaps fizzle completely? Seek out its exact position with the map here, and see for yourself. Greg Bryant is editor of Australian S&T.
Partial Eclipse of the Moon On the morning of Sunday, June 26th, observers in the western half of the United States can watch a partial eclipse of the Moon before or during dawn. The full Moon, in Sagittarius, will be sinking low in the southwest and will set around sunrise. The entire eclipse happens in a dark sky over much of the Pacific Ocean, including Hawaii. The West Coast sees all but the
Partial Eclipse of the Moon June 26, 2010
stage of the eclipse, the dark red-brown eclipse’s final stages before the Moon sets umbra of Earth’s shadow will cover the and the Sun rises. In the Mountain and northern 54% of the Moon’s diameter, part of the Central time zones, the partial as shown in the diagram below left. The eclipse will still be under way when the Moon sets. East of there the Moon sets Partial Lunar Eclipse, June 25–26, 2010 before the partial eclipse even begins. Eclipse event CDT MDT PDT HST At the deepest
North
PENUMBRA
Penumbra first visible?
4:30 a.m.
3:30 a.m.
2:30 a.m. 11:30 p.m.
Partial eclipse begins
5:17 a.m.
4:17 a.m.
3:17 a.m.
12:17 a.m.
Mid-eclipse
—
5:38 a.m.
4:38 a.m.
1:38 a.m.
Partial eclipse ends
—
—
6:00 a.m.
3:00 a.m.
Penumbra last visible?
—
—
—
3:45 a.m.
Partial eclipse ends 13:00 UT
Mid-eclipse 11:38 UT
Partial eclipse begins 10:17 UT
Moon enters penumbra 8:55 UT (unobservable)
S&T: DENNIS DI CICCO
Moon leaves penumbra 14:22 UT (unobservable)
West
East
UMBRA
Moon’s pat
h
Left: The northern half of the Moon will skim through Earth’s umbra (dark shadow core) during this eclipse. Less noticeable will be the first and last stages of the eclipse, when the Moon is in the penumbra, the shadow’s pale fringe.
South
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Celestial Calendar
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Entire eclipse visible
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Daytime (Moon not up)
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penumbral phases of the eclipse occur when the Moon is only within the penumbra, or pale outer fringe, of Earth’s shadow. The weak, pale gray penumbral shading is detectable only within about 45 minutes of the partial eclipse’s beginning or end, depending on sky conditions and how carefully you look! You can think of this lunar eclipse as a warmup for the big one that’s coming in six months. Late on the night of December 20–21, 2010, the Moon will be totally eclipsed high in a dark sky for all of North America. That will be our fi rst total lunar eclipse in almost three years. Mark your calendar. — Alan MacRobert
Find your location to see whether the Moon will set or rise during any phase of the eclipse for you. Because an eclipsed Moon is always full, it sets almost at the same time the Sun rises on the opposite horizon, or vice versa.
Ceres Crosses the Lagoon Nebula M
18h 20m
18h 00m
17h 40m
M21 May 1 11 21
X
17h 20m
OPHIUCHUS M20
Jun 1 M8
Path o
11
M28
21
f Cere
s
Q –25°
Jul 1
L
11
SAGITTARIUS
Star magnitudes 3 4 5 6 7 8
21 Aug 1 11 21
May 29 30
M8
5 Sgr
31
7 Sgr Jun 1 2
Path Mag. 7.3
of C
3
eres
4 5 6
Ceres is magnitude 7.5 (similar to the “mag 7.3” star labeled on the image) when it crosses M8 in Sagittarius as May turns to June. On both charts, the tick marks are for 0:00 Universal Time on the dates indicated; this falls on the afternoon or evening of the previous date in the longitudes of the Americas. Put a pencil dot on Ceres’s position for when you plan to observe!
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IMAGE: EVERTON ALLEN; DATA: SKY & TELESCOPE
Ceres, the l argest and first-discovered asteroid, is the only “dwarf planet” (by modern designation) easily visible to amateurs; the next brightest is 14th-magnitude Pluto. Right now Ceres may be familiar to only a tiny portion of humanity, but we can expect it to gain global star status in February 2015 when NASA’s Dawn spacecraft takes up orbit around it and starts imaging its unknown landscape in detail. In late May and early June Ceres passes just south of M8, the Lagoon Nebula in Sagittarius, as plotted below right. The asteroid will be magnitude 7.5, in range of good binoculars. You’ll have to wait up until about 1 a.m. for Sagittarius to climb fairly high in the south-southeast, and by that time the light of the waning gibbous Moon will flood the area. In fact the Moon passes right through that part of Sagittarius on the nights of May 28–29 and 29–30. Ceres reaches opposition on June 18th at magnitude 7.2. Follow it as it fades through the summer (passing magnitude 8.1 on August 1st) using the upper chart. Make the acquaintance of Ceres, follow it along, and when it becomes famous, you can say you knew it quite personally back in the day. ✦ — Alan MacRobert
)'(' Polynesian Island Eclipse Tour Tahiti, Moorea, and Easter Island July 9th–14th, 2010
J
oin Sky and Telescope magazine editors Robert Naeye, Dennis di Cicco, and contributing editor Kelly Beatty, in July 2010 for an eclipse tour full of mystery and fantasy. Watch 4½ minutes of totality on Easter Island, then relax in pure luxury at 5-star resorts inTahiti and Moorea. Enjoy only the finest accommodations aboard our specially chartered A340-300 Air Tahiti Nui aircraft with available business and first class upgrades with the expert service of the Polynesian staff. Sign up today! — $4995/person
www.SkyandTelescopeTours.com worldmags & avaxhome
1-866-668-0SKY
ALL STARS POINT TO . . . Magdalena Ridge Observatory Socorro, NM www.mro.nmt.edu
In the fall of 2006 we completed the installation of the 40.375 foot Observa-DOME at Magdalena Ridge Observatory which will house a 2.4 Meter Telescope.
[email protected]
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Sue French Deep-Sky Wonders
Southern Skies Scorpius and its neighbors host an unparalleled visual feast. Southern skies, have you ever noticed southern skies? Its precious beauty lies deep beyond the eye, And it goes rushing through your soul like the stories told of old. — Allen Toussaint, Southern Nights
On sable nights the southern sky is magnificent at this time of the year, and those who probe its depths with telescopes greet a wealth of celestial treasures. But observers at mid-northern latitudes are limited in just how far south they can survey. With that in mind, I’ve chosen a small sample of deep-sky wonders from the southern sky, beginning just below the celestial equator and ending with a marvelous sight that hugs my horizon in upstate New York. Let’s start our tour with the obscure planetary nebula Shane 1 (PK 13+32.1), lying 1.3° south of Sigma (σ) Serpentis. Through my 6-inch (152-mm) reflector at low power, I can easily pinpoint Shane 1 in a V of 10th- to 12th-magnitude stars. The V is 18′ tall, very slender, and its western side is slightly curved, as shown at lower right. A small triangle of stars marks the southern point. The middles of its sides are marked by Shane 1 (east) and an 11.6-magnitude star (west).
Shane 1 is a tiny thing, measuring only 6″ × 5″. Despite their size, diminutive planetaries often have a certain something that whispers, “I am not a star.” They may not appear sharp enough or quite the right color for a star. To me, Shane 1 looks like the ghost of a star. A narrowband or O III nebula filter betrays the planetary’s nature, for when viewed through such a filter, Shane 1 outshines the star to its west. My 10-inch reflector at high power adds a faint central star, a blue-gray hue, and some dimension to the nebula. Shane 1 is listed at magnitude 12.8, but it seems about a half magnitude brighter to my eye. Charles Donald Shane, then director of Lick Observatory, discovered Shane 1 while examining the Lick propermotion survey’s first-epoch photographic plates, taken in the 1940s and 1950s. A recent catalog places Shane 1 roughly 31,000 light-years away. Now drop down to NGC 5897, which is shown on page 66. This globular cluster sits pretty 1.7° southeast of Iota (ι) Librae. In my 6-inch scope at 38×, it’s visible as a very soft glow cradled by a shallow arc of three 8th-magnitude stars. At 112×, NGC 5897 is a lovely sight. It spans about 7½′ and clasps a large, somewhat brighter core. At least a dozen stars of mixed brightness sparkle within the cluster, and an 11th- and 12th-magnitude star pair guards
16h 20m
16h 22m
A Summer Smorgasbord Const.
Magnitude
Size/Sep.
RA
Dec.
Shane 1
Planetary nebula
Ser
12.8
6″ × 5″
16h 21.1m
–00° 16′
NGC 5897
Globular cluster
Lib
8.5
11.0′
15h 17.4m
–21° 01′
54 Hydrae
Double star
Hya
5.1, 7.3
8.3″
14h 46.0m
–25° 27′
NGC 5694
Globular cluster
Hya
10.2
4.3’
14h 39.6m
–26° 32′
NGC 5986
Globular cluster
Lup
7.5
8.0′
15h 46.1m
–37° 47′
NGC 6072
Planetary nebula
Sco
11.7
98″ × 72″
16 13.0
NGC 6231
Open cluster
Sco
2.6
14.0′
16h 54.2m
h
m
–36° 14′ –41° 50′
Angular sizes and separations are listed from recent catalogs. Visually, an object’s size is often smaller than the cataloged value and varies according to the aperture and magnification of the viewing instrument. Right ascension and declination are for equinox 2000.0.
SERPENS +1o S Star magnitudes
Type
Shane 1 POSS-II / CALTECH / PALOMAR OBSERVATORY
Object
6 7 8 9 10 11
+0o
Shane 1
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Deep-Sky Wonders
16h Shane 1
M12 M10
M5
S
E
15h 0o
SER
D
OPHIUCHUS LIBRA
M107
SER
Star magnitudes
M9 1 2 3 4 5
I –20o
M80
5897 58
M62
C
6268
5694
HYDRA
M6
SCORPIUS
54
S
M4 Antares
M19
M
6072
6242
6231
Q
LUPUS
CEN
H 5986 –40o
Z
its north-northwestern edge. In my 14.5-inch reflector at 170×, NGC 5897 looks much like a rich open cluster. It covers about 10′, with several of its brightest stars sprinkled across its eastern half. If you have trouble locating NGC 5897 or 5694 (discussed below) using the chart above, these objects are shown on page 57 of Sky & Telescope’s Pocket Sky Atlas. This page and several others are available as free downloads at SkyandTelescope.com/psa. Our next two targets are in Hydra, the Water Snake, though it’s more fun to think of them as occupying
Noctua, the Night Owl. This reputedly wise raptor was first depicted on Alexander Jamieson’s 1822 celestial atlas. Flown from modern star charts, little Noctua once stood upon Hydra’s tail and occupied some of the territory belonging to Libra and Virgo. Our first owlish stop is the colorful double star 54 Hydrae. The pair is delightfully split with my 130-mm refractor at 63×. The yellow-white primary holds a golden companion east-southeast. William Herschel discovered this double in 1783 and described the companion as bluish red. What color do you see? Also in Noctua, the globular cluster NGC 5694 sits along the western side of a 53′ zigzag of four 7th-magnitude stars. Through my 6-inch reflector at 38×, NGC 5694 is a little fuzzball making a 2½′ curve with a north-south pair of stars, magnitude 10½. The cluster bares no stars even at 176×, but it’s rather attractive, with an intense, almost starlike center. The globular is fairly bright to a diameter of about 1′, and a faint halo doubles its size. NGC 5694 is intrinsically brighter and larger than NGC 5897, but it looks smaller and fainter because it’s much farther away — 113,000 versus 40,000 light-years. Yet the loose appearance of NGC 5897 is not solely due to its proximity. The stars of NGC 5694 are 400 times more densely packed in the center. Next swoop down to NGC 5986, the brightest globular cluster in Lupus. My 105-mm refractor at 87× reveals a mottled glow with hints of resolution. A brighter foreground star garnishes its eastern side. In my 10-inch reflector at 187×, NGC 5986 is a granular haze flecked with stars across much of its 5′ face. My 14.5-inch scope shows stars right to the center. At a distance of 34,000 light-years, NGC 5986 is the
NGC 5897
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DANIEL VERSCHATSE / OBSERVATORIO ANTILHUE, CHILE
L
16h
16h 10m
16h 00m
Star magnitudes
6072 4 5 6 7 8 9
SCORPIUS
15h 40m
15h 50m
–36o
LUPUS Q h
H
5986
–38o
6268
Tr 24 IC 4628 B48
vdB-Ha 205 Ru 122
vdB-Ha 211
6231
ζ²
ζ¹
ADAM BLOCK / NOAO / AURA / NSF
nearest of our three globulars. This is enough to make it appear brighter in our sky than NGC 5897, despite being more obscured by interstellar dust and inherently a bit less luminous. Just 1.4° east-northeast of Theta (θ) Lupi, the planetary nebula NGC 6072 resides in neighboring Scorpius. Through my 6-inch scope at 112×, it appears roundish with dimmer patches inside. A yellow, 8.6-magnitude star hovers north. My 10-inch scope at 118× shows an east-west oval with fainter ends, a suggestion of annularity, and a dim star superposed on the northeastern side. The nebula stands out nicely with a narrowband or O III filter. At 220× it’s about 1¼′ long, two-thirds as wide, and harbors a brighter spot near the center. NGC 5986 and NGC 6072 are too far south for observers in the northern reaches of Canada and Europe, but they’re approximately 10° above my horizon. By contrast, the False Comet tickles my horizon and cannot be seen in its entirety from any place much farther north. Canadian amateur Alan Whitman pointed out this striking “comet-like Milky Way patch” while attending the Texas Star Party in 1983. With his unaided eyes, Whitman saw NGC 6231 as the coma of the comet, and Zeta1 (ζ1) and Zeta2 (ζ2) Scorpii as a nucleus at its leading edge. The comet tail arcs gently northward, formed mostly by the misty glow of Trumpler 24. The False Comet’s splendor isn’t obvious to the unaided eye from my latitude, but its components are a lovely sight in my husband’s 15×50 image-stabilized binoculars — even from our family camp, where the comet’s nucleus crests a mere 3.3° above the horizon. The Zeta stars shine in nicely contrasting hues of white and gold, with the speckled glow of NGC 6231 to their north. Above this, a large arc of loosely scattered stars fans to the north-northeast for about 1¾°. Some sources identify this as Trumpler 24, but in his 1931 doctoral dissertation, Swedish astronomer Per Arne Collinder defined a larger group, Collinder 316, overlapping Trumpler 24 and centered farther southwest. Perhaps too scattered to rate open-cluster status, these groups are part of a youthful association of stars known as Scorpius OB1.
The region north of Zeta Scorpii, sometimes called the False Comet, is one of the most magnificent fields in the entire sky.
The False Comet is a beautiful naked-eye sight from the Winter Star Party in the Florida Keys. Viewed from Florida through New York amateur Betsy Whitlock’s 105mm refractor, NGC 6231 is a stunning, ¼° collection of 80 mixed bright and faint stars, while the comet’s tail is a conspicuous gathering of well over a hundred stars. My 10-inch reflector turns up more comet pieces. Within Trumpler 24, van den Bergh-Hagen 205 is a little knot of 6 stars, Ruprecht 122 shows a small misty sprinkling of faint suns, and the emission nebula IC 4628 is a large east-west glow. A few tempting targets fence the comet’s tail. NGC 6242 is a prominent 9′ collection of 25 stars, most confined to a bar tipped northnorthwest. Dimmer and smaller, NGC 6268 has many of its 25 stars arranged in two parallel lines. The dark nebula Barnard 48 is a 35′ × 10′ star-poor strip leaning northeast, and van den Bergh-Hagen 211 is a dim group dominated by an east-west line of stars. The False Comet is truly a precious beauty in our southern skies. Enjoy! ✦ Sue French welcomes your comments and questions at
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Gary Seronik Telescope Workshop
Making Sonotube Beautiful Transforming a plain cardboard tube into something colorful is easy.
be afraid of me — all I have to do is look at it and it runs. Sorry, I couldn’t resist. But it’s true that, for me at least, one of the most difficult tasks in completing a telescope is giving it an attractive finish. And usually, the most troublesome part is the tube. Luckily, there is a paintfree solution that works great. Last April I mentioned using a model airplane covering called MonoKote, which prompted several readers to ask for more details. MonoKote (www.monokote.com) comes in a veritable rainbow of colors and several styles. The great thing about using it as a tube covering is that you can use it on the ATM’s old standby, concrete-form tubing, even if the tube’s exterior is waxed. But because the material behaves like shrink wrap, any dents or imperfections in the tube will show through, just like with paint. Also, if you choose a light color, you may want to give your tube a quick coat of white paint beforehand to prevent printing on the tube from showing through. Because I’ve used darker, solid colors, I haven’t had to do this. Applying the material is straightforward, but there are a few tricks that’ll make the process go easier. First, you’ll need to round up a straightedge, hobby knife, and heat gun. The latter is often sold as a paint stripper and it’s essentially an insanely hot hair dryer (a regular hair dryer won’t work). A heat gun will set you back $15 to $30. But chances are a neighbor or friend has one you can borrow. MonoKote comes in rolled sheets that are 25¾ inches wide and about 73 inches long (65 by 185 cm). If your highschool math is a bit rusty, the formula for the surface area
The material comes in a roll and is easily cut with a hobby knife guided by a straightedge.
GARY SERONIK (3)
Paint doesn’t like me. I think it might even
MonoKote is a durable plastic material used as model airplane skin. It’s also an excellent paint substitute for telescope tubes.
of your tube is simply the length multiplied by the outside diameter multiplied by pi (L × D × π). You should also add 1/4 - to 1/2-inch of material for overlaping seams. A single roll is usually enough for 8-inch and smaller scopes. Use the straightedge and hobby knife to cut the MonoKote and trim off any clear edges — there’s usually an 1/8 inch or so clear edge at the top and bottom of the roll. Next, peel off the transparent plastic backing to expose the heat-sensitive adhesive. This is the surface that goes against the tube. Take your first piece and lay it on the tube in such away that the ends meet on the opposite side of the tube from the focuser. Although a finished seam is difficult to see, there’s no point it having to look at it every time you use the scope! Temporarily tack the piece in position with short pieces of tape. Use the heat gun to gently apply heat to the seam. The idea here is to heat the MonoKote enough to activate the adhesive so that the overlapping area sticks together. Once you accomplish this task, remove the tape and apply heat to the entire tube, starting at the seam. Use a slow, sweeping, back-and-forth motion, moving up and down the length of the tube and advancing along its circumference an inch or two after each completed pass. Hold the heat gun two or three inches away from the surface of the tube, and keep moving at a rate of about one inch per second. If you hold the heat gun stationary too long, or hold it too
68 June 2010 sky & telescope
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FOCUS ON
close to the tube, you risk melting a hole in the material. As you heat the MonoKote, you’ll see it expand and then shrink down to contact the tube as it cools. I have to go over the entire tube three or four times before the material has settled and fully contracted. Don’t worry about wrinkles initially — they usually smooth out when everything cools. You can attack those that remain with the heat gun. If that fails, try reheating the area and smoothing it with your hand, protected with an oven mitt. Occasionally, you’ll find pockets of air trapped under the plastic surface. You can eliminate these pockets by pricking the bubble with a needle, then reheating the area. And if you should melt a hole in the covering, simply patch it with a small piece of scrap material. After you’ve completed the job you’ll be rewarded with a beautiful tube that has a durable, high-gloss finish. And unlike paint, MonoKote never runs! ✦
Sola Fide Observatory – Austin, Minnesota The ASH-DOME pictured is a 12’6”-diameter, electrically operated unit. The observatory dome shelters a 10-inch, f/10 Dobbins telescope. The observatory is used for personal observing and by local amateur astronomy groups year-round.
ASH MANUFACTURING COMPANY P.O. Box 312, Plainfield, IL, USA 60544 815-436-9403 • FAX 815-436-1032 www.ashdome.com Email:
[email protected] Ash-Dome is recognized internationally by major astronomical groups, amateurs, universities, colleges, and secondary and primary schools for its performance, durability, and dependability. Manual or electrically operated units in sizes from 8 to 30 feet in diameter available. Brochures and specifications upon request.
springer.com
For the biggest and best list of practical astronomy books, visit www.springer.com/sky
A Spectroscopic Atlas of Bright Stars Series: Astronomer's Pocket Field Guide Written by Jack Martin 2010, 205 pages 87 illustrations, Softcover ISBN: 978-1-4419-0704-2 Price: $29.95 Are you ready for a different way of looking at the stars? Do you want to understand more about what you are seeing through your telescope?
Contributing editor and ice hockey fanatic Gary Seronik builds scopes and observes the night sky at his home in Victoria, British Columbia, Canada. He can be contacted through his website, www.garyseronik.com.
The first amateur atlas to chart the observable spectroscopic stars. An essential tool for all amateur astronomers interested in practical spectroscopy. Contains spectroscopic images, profiles and data on bright and familiar naked eye stars. A user-friendly guide that is equally applicable to amateur astronomers and college undergraduates. Tables and spectroscopic are terms fully explained.
The 100 Best Astrophotography Targets A Monthly Guide for CCD Imaging with Amateur Telescopes Series: Patrick Moore's Practical Astronomy Series Written by Ruben Kier 2009, XXI, 360 p. 115 illus. in color. Softcover ISBN: 978-1-4419-0602-1 Price: $34.95 What do you photograph? Will something that looks amazing as you peer at it through a telescope look the same in a photograph? There are so many dazzling sights in the night sky. How to choose? Ruben Kier has some answers for you. The first guidebook to specifically target the best objects for backyard astrophotography. Organized into monthly chapters so readers can quickly find the best targets for any night of the year. Helps readers to locate and quickly identify objects that will be both easy to image and provide great visual appeal.
Available in a wide range of colors and styles, MonoKote was the tube finish of choice for the author’s recent telescope projects.
Easy Ways to Order for the Americas Write: Springer Order Department, PO Box 2485, Secaucus, NJ 07096-2485, USA Call: (toll free) 1-800-SPRINGER Fax: +1(201) 348-4505 Email:
[email protected] or for outside the Americas Write: Springer Distribution Center GmbH, Haberstrasse 7, 69126 Heidelberg, Germany Call: +49 (0) 6221-345-4301 Fax: +49 (0) 6221-345-4229 Email:
[email protected] Prices are subject to change without notice. All prices are net prices.
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Exploring Planetary Nebulae
NGC 6369, the Little Ghost Nebula in Ophiuchus, displays intricate detail in this false-color image from the Hubble Space Telescope. NASA / HUBBLE HERITAGE TEAM / STSCI / AURA
Flowers l of h the ight k Sky Ted Forte
PLANETARY NEBULAE
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M2-9
i
S ER PENS C AUDA
d OPHI UC HUS
S AGI TTAR I US –20°
6309
6369
IC 4732
e
h
Antares
6026 r
h
SCORPIUS 6337
–40°
L UP
18h
20h
19h
g
C Y GNUS
16h
18h
Star magnitudes
son to endure the long summer twilight and wait patiently for darkness. Any summer night offers dozens of bright planetaries to enjoy. Like unfolding flowers in a cosmic garden, they blossom in mysterious shapes and subtle colors. The term planetary nebula is an unfortunate misnomer. Sir William Herschel fi rst used it to describe the object that he cataloged as H IV-1 (now known as NGC 7009, the Saturn Nebula). He was probably influenced by its tiny disk, its ability to hold magnification, and perhaps its similarity in color to the planet Uranus, Herschel’s most famous discovery. In fact, planetary nebulae have nothing to do with planets; we now think that they’re a late stage of stars comparable to, or a little more massive than, the Sun. We’re fortunate to have so many of these fascinating objects in our sky, for like flowers, they’re rather shortlived, lasting just a few tens of thousands of years at best. They’re fairly plentiful because there are so many Sunlike stars — enough to form roughly one planetary nebula each year in the Milky Way Galaxy. A planetary nebula is formed when a dying star throws off its outer layers. This leaves an extremely hot exposed core which emits most of its energy as ultraviolet radiation. The expanding cloud of cast-off material absorbs this ultraviolet energy and re-emits much of it as visible light, in a process similar to what occurs in a fluorescent light bulb. The brightest emissions in visible wavelengths are from doubly ionized oxygen (O III) and excited hydrogen (Hα and Hβ). The path from main-sequence star to planetary nebula leads through several stages of development that are characterized by repeated expansions, instability, and mass loss. There are different models to explain the complex shapes that planetary nebulae take. The expanding clouds may be shaped by irregular outflows, differential speeds of the material moving away from the star, sporadic mass ejections, twisting magnetic fields, disks of debris, and the influence of a binary partner. Whatever the forces may be, they conspire to form a variety of complex shapes. What we see is also defined by our line of sight; even similarly shaped objects appear different when viewed from different angles. Some planetary nebulae appear as tiny bright disks, others are large delicate wreaths, and still others tenuous transparent ghosts. They can be rings, disks, butterflies, or cylinders of blue, green, or nebular gray. It’s this diversity that makes these objects so fascinating to observe.
Planetary nebulae are often classified by their visual appearance. In the system devised by the Russian astrophysicist Boris Vorontsov-Velyaminov, they’re divided into six main types and a few subtypes. A Class I planetary presents a stellar image, a tiny disk so small that it’s indistinguishable from a star. Of course this description is both subjective and variable. It depends on several factors, including the seeing conditions, the aperture and optical quality of the telescope, the magnifi-
1
Star magnitudes
FANS OF PLANETARY NEBULAE have ample rea-
0 1 2 3 4 5
2 3 4 5
16h
17h
DR AC O 6742
b 16 +40°
13
LYRA
HER C UL ES
Vega
a `
M57 6765 51
+20°
6210
`
These charts label only stars that are useful for locating the planetary nebulae discussed in this article. There are detailed charts for the areas shown in black; the remaining nebulae can be located using Sky & Telescope’s Pocket Sky Atlas or charts on our website, as described in the article.
COME IN A FANTASTIC VARIETY OF SIZES, COLORS, & SHAPES. Sk yandTelescope.com June 2010 71
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Exploring Planetary Nebulae
cation, and the skill of the observer. Many planetaries that aren’t officially in Class I may appear stellar in some circumstances. IC 4732 in Sagittarius is a typical example of a stellar planetary. Although it’s only a little more than 1° northwest of the great globular cluster Messier 22, this nebula is challenging to locate, even
with a Go To telescope, because it’s camouflaged in a very crowded star field, as shown below. There are two powerful weapons in the amateur’s arsenal that can help you bag this sort of beast. The first is a computer with good star-charting software that exceeds the depth of even the biggest
printed star atlas. If you bring your laptop computer into the field, you can scale a detailed map to the exact telescopeeyepiece combination that you’re using, and orient the field to match your view through the eyepiece. The second weapon, the nebula filter, preferentially passes the specific wavelength that most planetary nebulae are brightest in — the green O III band. By darkening all but the narrow window of wavelengths around that OIII emission, the filter can increase the contrast between sky and nebula. You should practice to perfect the technique known as “blinking” with a filter. Hold the filter between thumb and forefinger and move it into and out of the light path by passing it between eye and eyepiece. The filter dims stars dramatically, making nebulae appear brighter by contrast. As you repeat this over and over, a planetary nebula appears to blink. Larger objects can benefit from screwing a nebula fi lter into the barrel of the
Star magnitudes
POSS-II / CALTECH / PALOMAR OBSERVATORY
IC 4732
5′
18h 35m
18h 30m
–22°
IC 4732 –23° 23
Representative Planetary Nebulae Object
Class
Const.
Mag.
Size
RA
Dec.
IC 4732
I
Sgr
12.8
3″
18h 33.9m
–22° 39′
NGC 6742
IIc
Dra
13.4
31″
18h 59.3m
+48° 28′
NGC 6210
II+IIIb
Her
9.2
48″ × 30″
16h 44.5m
+23° 48′
6642 NGC 6309
M22
NGC 6026 24
–24°
All the detailed charts in this article show stars to magnitude 10.5. Many planetary nebulae are visible only at high magnification, so charts with fewer stars are often inadequate. In extreme cases, even a Digitized Sky Survey image (shown at left) can’t distinguish the nebula from a star.
3 4 5 6 7 8 9 10
NGC 6337
IIIb+VI IV IV
Oph Lup Sco
11.5
52″
12.5
54″ × 36″
12.3
49″ × 45″
h
m
–12° 55′
h
m
–34° 33′
h
m
–38° 29′
h
m
17 14.1
16 01.4
17 22.3
25
NGC 6369
IV
Oph
11.4
58″ × 34″
17 29.3
–23° 46′
SAGITTARIUS
NGC 6765
V
Lyr
12.9
38″
19h 11.1m
+30° 33′
M2-9
VI
Oph
14.7
115″ × 18″
17h 05.6m
–10° 09′
6644
–25° 6638
h
Angular sizes are from recent catalogs. Visually, an object’s size is often smaller than the cataloged value and varies according to the aperture and magnification of the viewing instrument. Right ascension and declination are for equinox 2000.0.
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19h 10m
19h 00m
18h 50
19h 00m
18h 50m
DRACO
+50°
NGC 6742
ADAM BLOCK / NOAO / AURA / NSF
6742 +48°
16
LYRA
2′
NGC 6742, a Class II planetary nebula in Draco, appears as a tiny, crisp-edged, nearly uniformly bright disk in most backyard telescopes.
of the Dumbbell and turns this familiar object into something exotic. Planetaries that appear as smooth disks fall into Class II. They’re further broken down into sub-categories based on whether they’re (a) brighter toward the center, (b) uniform in brightness, or (c) have traces of ring structure. The differences may be less than obvious unless you develop a particularly discerning eye, and conditions can greatly affect your perception.
eyepiece. Filters enhance some planetaries more than others, but most are improved to some degree, and some planetaries may be invisible without filters. It’s important to experiment. And don’t hesitate to try a filter even on bright objects; you might discover structure and detail that isn’t apparent in the unfi ltered view. Messier 27, the Dumbbell Nebula, is a great example. It’s a showpiece in any case, but a filter enhances the faint outer reaches
N
N
2′
2′
ADAM BLOCK / NOAO / AURA / NSF
NGC 6210
STEFAN BINNEWIES / JOSEF PÖPSEL
NGC 6309
An example of a Class II planetary is NGC 6742, a 13.4-magnitude disk in Draco, which you can locate using the chart at left. It’s classified as IIc, meaning that it should be a bit annular (ring shaped) with a darker center. However, in my 18-inch f/4.5 reflector it always appears rather uniform to me, and in my 8-inch Schmidt-Cassegrain telescope I see it as only slightly more than stellar. A better-known example is NGC 6210 in Hercules, sometimes known as the Turtle Nebula, shown at bottom left. Unlike IC 4732 and NGC 6742, the Turtle is quite bright, though very small, making it relatively easy to locate without highly detailed charts. It‘s plotted in Sky & Telescope’s Pocket Sky Atlas on page 54. (All the Pocket Sky Atlas pages referenced in this article are available as free downloads at SkyandTelescope.com/psa.) The Turtle is exciting because it shows features that are present in many planetaries but are only visually detectable in a few cases. All planetary nebulae have central stars, but not all of these are visible. In some cases, the central star is masked by the nebula; in others, it’s simply too faint to see. Planetaries radiate in wavelengths that produce colors, mostly red from Hα, green from O III, and blue from Hβ. But our eyes are not very sensitive to red light, so we mostly see planetary nebulae as blue-green — or gray if the light is not intense enough to stimulate color vision. Finally, many planetaries have a hierarchical structure of nested shells, the outermost being known as the halo. Photographs show halos on many planetaries, but they’re usually too faint to be detected visually. The Turtle shows color — but is it blue or green? When the seeing is good, its central star may be visible in scopes with 12 inches or more of aperture. The Turtle is also one of perhaps a dozen planetaries whose outer halos can be seen — though not always easily — through the eyepiece Far left: NGC 6210, the Turtle Nebula, is classified as II+IIIb. That means that its disk has both regular and irregular aspects, and a hint of a ring structure. Left: NGC 6309, the Box, is classified as IIIb+VI, an irregular disk with some ring structure and anomalous aspects.
Sk yandTelescope.com June 2010 73
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Exploring Planetary Nebulae
19h 10m
19h 00m
17
G
L +32° NGC 6765
19
LYRA STEFAN BINNEWIES / JOSEF PÖPSEL
+31° 6765 M56 +30° 5′
C
N
X –34° 6026 NGC 6026 POSS-II / CALTECH / PALOMAR OBSERVATORY
STEFAN BINNEWIES / JOSEF PÖPSEL
NGC 6337
2′
Star magnitudes 3 4 5 6 7 8 9 10
LUPUS
–36°
5′
Q
NGC 6337 (lower left) and 6026 (lower center) are examples of Class IV, the ring-shaped nebulae. An even more striking example is NGC 6369, the Little Ghost, shown on page 70. NGC 6765 (top) is assigned to Class V, the irregular planetary nebulae.
of backyard telescopes. Class III is assigned to those planetary nebulae that have irregular disks. They’re further subdivided into IIIa nebulae, which are very irregular, and IIIb, which have traces of a ring structure. One favorite is NGC 6309, a class IIIb nebula in Ophiuchus, shown on the bottom of page 73. It lies 1° 39′ due west of Nu (ν) Serpentis and is charted on page 56 of the Pocket Sky Atlas. NGC 6309 is sometimes called the Box because its elongated disk may appear square when viewed through a fi lter. Annular (ring-shaped) planetaries are assigned to Class IV. The most promi-
nent members of this class always elicit a response of startled pleasure from novices, and are star-party favorites. Most of them, however, appear as solid disks in all but the largest apertures, with only a hint of a darkened center to tease the observer. Their actual architecture is often a subject of debate. Are they truly donut shaped? Are they spheres that appear ringlike because we look through more material on the edges? Or are they cylinders or cones seen face on? Messier 57, the Ring, is the most famous of the class, but several lesserknown members are worth a look. NGC 6026 in Lupus, shown and charted above,
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16h 00m
15h 50m
is a challenge for an 8-inch scope. It appears as a circular disk with an obvious central star in most amateur instruments. NGC 6337 in Scorpius, depicted at left and charted on page 58 of the Pocket Sky Atlas, is nicknamed the Cheerio Nebula and gives a better hint of annularity, with some observers unabashedly describing a ring. NGC 6369, the Little Ghost in Ophiuchus (shown on page 70 and charted on page 56 of the Pocket Sky Atlas), is less ambiguous still, a clearly annular ring. NGC 6765 in Lyra, shown and charted at top, has an irregular form characteristic of a Class V planetary nebula. It’s often described as dual-lobed or streaklike in larger telescopes, or as a small, faint, irregular disk that’s brighter to the north in smaller scopes. Observers up to a challenge might try the tiny object in Ophiuchus known as
Minkowski’s Butterfly (M2-9), a representative of Class VI (anomalous form). It lies 3½° degrees northwest of NGC 6309; see SkyandTelescope.com/m2-9 for a detailed chart. Save this one for a night of good seeing, for you’ll need to pump up the power above 300×. Filters are little or no help. A 12-inch scope should be able to reveal the bipolar structure, and people with larger scopes describe remarkable detail. How large a scope it takes to detect M2-9 is a subject of debate, and if you succeed with a 6-inch or smaller scope, you can count yourself a member of a very exclusive club! Don’t be surprised if you develop a strong affinity for these fascinating objects; they’re the unchallenged favorites for many seasoned observers. That may be because we feel a connection to them. Not only do they foretell the probable future of our star, they’re also responsible for distributing into the stellar medium some of the elements that enrich subsequent generations of stars with the building blocks of planets, and of people. ✦ Ted Forte is chair of the Astronomical League’s Planetary Nebula Club.
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A pair of stars in a very tight orbit lies at the heart of Minkowski 2-9. Material from one of these stars forms an accretion disk around them, and twin jets shooting out at right angles to this disk sculpt the planetary’s exotic shape.
For more information call Robert Stephens at (909) 948-2205, or email your questions to
[email protected]
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Sean Walker Gallery
▴ WINTER RETREAT Jeff Peronto The Milky Way spanning from Puppis (left) to Perseus cut a bright swath high across the sky this year at the annual Winter Star Party held on West Summerland Key in Florida. Details: Canon EOS 5D DSLR with 15-mm fisheye lens. 30-second exposure at ISO 3200.
▶ LIFT
OFF! John H. Pilarski Space Shuttle Endeavour leaves Earth on mission STS-130 last February 8th, creating a luminous arc in this time exposure during what may have been the final scheduled shuttle night launch. Details: Canon EOS 5D DSLR with 16-mm lens. Total exposure was 3 minutes at ISO 100, f/22.
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▶ COPERNICAN DEBRIS Paolo Lazzarotti Thousands of tiny craterlets litter the area surrouning the 56-mile-wide (90-km) crater Copernicus. Most of these tiny pockmarks were created by the ejecta exhumed during the impact event that formed Copernicus hundreds of millions of years ago. Details: 12½-inch Lazzarotti Optics Gladius Dall-Kirkham telescope with LVI-1392 PRO video camera. Two-frame mosaic, each a stack of 120 video frames.
CARINA STARBIRTH Yuri Beletsky The Carina Nebula, NGC 3372, is the brightest nebula visible from the Southern Hemisphere. This spectacular photo records some of the faint extensions of the object, as well as numerous dark clots of gas and dust. Details: Takahashi FSQ-106ED astrograph with an SBIG STL-11000M CCD camera. Total exposure was 6½ hours through red, green, blue, and Hα filters.
▾
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Gallery
▴ RING OF FIRE Peter Burnside The annular eclipse of last January 15th appears to ignite the thin clouds as it sets over the hills of Qingdao, China. Details: Canon Digital Rebel DSLR with 100-mm lens. Single exposure of 1/200 second, ISO 100.
▶ NEBULOUS BRIDGE Scott Johnson This deep mosaic of the western edge of Monoceros reveals a lacy bridge of nebulosity connecting famous targets in the region: the Cone Nebula, NGC 2264 (top), and the Rosette Nebula surrounding the open cluster NGC 2244. Details: Takahashi FSQ-106 astrograph with an Apogee Instruments Alta U16M CCD camera. Total exposure was 6 hours through an Astrodon Hα filter. ✦
Gallery showcases the finest astronomical images submitted to us by our readers. Send your very best shots to
[email protected]. We pay $50 for each photo published in the magazine. See SkyandTelescope.com/aboutsky/guidelines. 78 June 2010 sky & telescope
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Princeton University Press . . . . . . . . . . . . . . 47
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Quantum Scientific Imaging, Inc. . . . . . . . . 82
Beta Electronics, Inc. . . . . . . . . . . . . . . . . . . 80
Rainbow Optics. . . . . . . . . . . . . . . . . . . . . . . 80
Bob’s Knobs . . . . . . . . . . . . . . . . . . . . . . . . . 81
Riverside Telescope Makers Conference
Celestron . . . . . . . . . . . . . . . . . . . . . . . . .17, 88
Scope City . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
CNC Parts Supply, Inc. . . . . . . . . . . . . . . . . . 80
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SCS Astro. . . . . . . . . . . . . . . . . . . . . . . . . . . . 80
Lessons from Solar Twins
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Skies Unlimited . . . . . . . . . . . . . . . . . . . . . . . 64
Fishcamp Engineering . . . . . . . . . . . . . . . . . 81
Sky & Telescope . . . . . . . . . . . . . . . . . . . . . . . 50
The Sun’s closest stellar analogs hold important clues to our own star’s past and future.
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Sky-Watcher USA. . . . . . . . . . . . . . . . . . . . . . . 7
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Hands On Optics . . . . . . . . . . . . . . . . . . . . . 42
Society for Astronomical Sciences. . . . . . . . 41
High Point Scientific . . . . . . . . . . . . . . . . . . . 41
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Hotech Corp. . . . . . . . . . . . . . . . . . . . . . . . . . 80
Springer US . . . . . . . . . . . . . . . . . . . . . . . . . . 69
InSight Cruises . . . . . . . . . . . . . . . . . . . .28, 29
Stella Vista Lodge . . . . . . . . . . . . . . . . . . . . . 83
International Dark-Sky Association . . . . . . . 79
Stellarvue . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79
iOptron . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
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JMI Telescopes . . . . . . . . . . . . . . . . . . . . . . . 64
Tele Vue Optics, Inc. . . . . . . . . . . . . . . . . . . . . 2
Khan Scope Centre . . . . . . . . . . . . . . . . . . . . 82
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Knightware. . . . . . . . . . . . . . . . . . . . . . . . . . . 81
The Teaching Company . . . . . . . . . . . . . . . . 39
Meade Instruments Corp. . . . . . . . . . . . .9, 19
TravelQuest International . . . . . . . . . . . . . . . 83
Metamorphosis Jewelry Design . . . . . . . . . . 82
University Optics, Inc. . . . . . . . . . . . . . . . . . 81
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Oberwerk Corp. . . . . . . . . . . . . . . . . . . . . . . . 81
Willmann-Bell, Inc. . . . . . . . . . . . . . . . . . . . . 81
Observa-Dome Laboratories . . . . . . . . . . . . 64
Woodland Hills Telescopes . . . . . . . . . . . . . 75
75
Deep-Sky Discovery An amateur planetary nebula finding shows that interesting deep-sky objects remain undiscovered.
Shooting Low
BOTTOM: RUBEN KIER; TOP: TRAVIS RECTOR (UNIV. OF ALASKA, ANCHORAGE) / NOAO / AURA / NSF, ET AL.
Improve your imaging techniques to capture beautiful photos of lowaltitude targets.
Walt Whitman’s Meteors Whitman’s poem “Year of Meteors” (1859–60) references several newsworthy events in U.S. history, including one of special interest to astronomers.
SkyandTelescope.com 800-253-0245
On newsstands June 1st! Sk yandTelescope.com June 2010 85
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Focal Point
Jim Bell
A Sea Change for NASA To continue America’s leadership in space, NASA needs to go in a new direction. A sea change has been proposed in the way NASA explores space (May issue, page 16). As a planetary scientist and strong supporter of human spaceflight, I’m excited by the potential of the proposed new plan to dramatically enhance both human and robotic exploration of our solar system. Under the proposal, NASA would get out of the rocket-making business and would instead contract out rocket design, test, and fabrication jobs to private industry. It’s not complete privatization, though: NASA would remain in the pilot’s seat for oversight, safety, mission assurance, and launch operations. NASA would partner with industry to spur innovation with prudent but minimal intrusion. Still, the controversial proposal has polarized the space community and thrust NASA and its mission back into the national spotlight. Opponents claim that scrapping many years of work on the Constellation program’s Ares rockets and Orion
spacecraft, and relying on new launchers, is too risky and would cede American leadership in human spaceflight. Supporters of the new proposal claim that Constellation was so far over budget, behind schedule, and technically troubled that it was doomed to cede our leadership anyway. For nearly 30 years NASA has been launching space shuttles to low-Earth orbit. Unfortunately, public and media interest in the shuttle and the International Space Station has dwindled. NASA’s 2004 “Vision” to return astronauts to the Moon by 2020 was a calculated gamble that a new lunar-focused program would again excite the nation about space exploration. But that gamble hasn’t paid off. Funding for Constellation has been inadequate, and interest in the Moon is weak among young people. Even many older NASA cheerleaders (like me!) are losing patience with a space program that hopes to take a decade or more just to get back to the Moon. Going
to Mars is ever farther away. The new plan has also been criticized for being vague. But the lack of specifics might make sense if the goal is to make engineers think outside the box and come up with new inventions and innovations in rocketry, including new heavy-lift boosters that could send astronauts to places such as near-Earth asteroids, the moons of Mars, and eventually Mars itself. Advances in rocketry could open up space to us all, like commercial airliners have opened up the skies. The proposal may be vague but it’s not naïve: it would be propelled by $6 billion over the next five years. The new plan could also be great news for robotic exploration. Planetary science, including missions to Mars, Jupiter, and elsewhere, would be funded at healthy levels. Expanded international science partnerships would be developed, with NASA leadership. And new robotic missions to the Moon, asteroids, and Mars would be added as precursors to human exploration, providing the information needed for astronauts to explore these places safely. Presidents since John F. Kennedy have realized that America’s space program is a global projection of its national power and personality. The new administration gets it; its plan for NASA is risky but bold. America will not continue to lead the world in space exploration if it’s not willing to reinvent NASA, to advance technology beyond the conventional, and to accept potential increases in risk in exchange for potentially greater increases in reward. ✦
JANE SANDERS
Jim Bell, President of The Planetary Society, is a professor of astronomy at Cornell University and lead imaging scientist for the Mars Exploration Rovers. A paperback version of his book Postcards from Mars will come out in late 2010. 86 June 2010 sky & telescope
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