EE
ac n 0 FR201lma yA k S
32
worldmags
for 2010 p. 36
THE ESSENTIAL MAGAZINE OF ASTRONOMY JANUARY 2010
Amateurs Breathe New Life into NASA Pictures p. 76
GALAXIES from the Dawn of Time New Hubble Pictures See Deeper than Ever p. 24
Where Is E.T.? p. 94 Nebulae and Clusters Galore p. 65 July’s Pacific Solar Eclipse p. 32 Probing the Sun’s Deepest Mysteries p. 22 Visit SkyandTelescope.com
worldmags
Invest in your enjoyment...
...and share the dividends for a lifetime. ™
Tele Vue APO refractors earn a high yield of happy owners. 25-years of hand-building scopes from 60 to 127mm apertures is why we see comments like: “Thanks to all at Tele Vue for such wonderful products.” •(More from R.C. of TX TV85 warranty card) “I love it, everything looks right, feels right, works right, fits right.” •(NP101) “After owning 12 telescopes, I found the consistent quality of Tele Vue the best!”—M.H.,CO •(TV60is)“A++++++++”—M.W.,AR •(TV60)“Stunning Stunning optics in a small scope.”—L.D.W.,UK •(NP101is)“It’s a pleasure owning the best”—G.T.,CA •(TV85) “I wanted quality optics & construction. I feel like I’ve finally gotten the scope I’ve always wanted wanted. Thanks!!”—D.H.,OK • (NP127is) “This will be the last telescope I will ever need to buy. Thanks for a superb instrument.” —M.S.,Canada •(TV102) “I wanted a quality scope that can be setup quickly. Amazing Amazing, the scope and mount of my childhood dreams perfected!”—B.L.,IL •(TV85)“Plan to keep it forever forever.”—B.W., VA
worldmags
®
Tele Vue Vi s i o n a r y
Unbelievable •(NP101) “Unbelievable Unbelievable, tack-sharp, flat widePerfect field views. color correction, outstanding at high powers! I love this scope!!”—D.H.,NY •(NP101is)“What a great instrument for imaging and viewing!”—R.G.,CA •(TV76)“Loved the NP101 so much, I wanted a smaller scope from TV.”—S.M.,MA •(NP127is)“Best in the world. WOW WOW!!!”—J.W.,MN
Wonderful scope! Excellent performance, •(TV85)“Wonderful magnificent build quality. Truly a scope to pass down. I love it.”—E.G.,RI down •(NP101)“Beats my expectations. Used 325x on Jupiter in great seeing! Wow Wow! I will proudly use this scope until I die die.”—K.V.,CA •(TV102)“I really feel like I’m driving a scientific tool when viewing. Easy to get lost in the image.”—P.M.,NY
•(TV76)“Pure quality instrument. Awesome views. Too busy viewing to send this (warranty card) in. Great multipurpose instrument for birding and astro use.” —W.E.,HI •(NP127is)“Best Best color correction for CCD imaging. My first views last night were remarkable remarkable.”—K.M.,NC •(TV85)“First look is everything I expected expected—a
•(TV85)Purchased because of ”1)positive reviews, 2)made in U.S.A. It’s everything reviews indicated
great little scope with typical TV quality.”—J.R.,CA •(NP101is)“Very well made made, excellent systems approach to the design.”—B.P.,NJ
•(NP101)“Tele Vue is simply the best; no ifs, ands, or buts about it. Thank you Al, David, and all the helpful folks at Tele Vue Vue.”—C.A.MA
and more.”—C.W.,CA •(TV76)“Best value for its quality”—R.S,FL •(NP127is)“Picked TV due to consistent high quality of products.”—D.M.,TX
Comments from recent warranty cards
Tele Vue Optics, Inc., 32 Elkay Drive, Chester, New York 10918 845.469.4551 www.TeleVue.com
worldmags
worldmags
worldmags
worldmags
1WT8QY6Q;QW
years ago a commitment was made to create a company that would offer the finest telescopes to astronomers everywhere. Today, we renew our commitment to the astronomical community. We vow to continue our tradition of engineering innovative products with the latest technologies that you will be proud to stand beside for a lifetime. Faithfully Yours,
Celestron
0 196 2 0 10
YYYEGNGUVTQPEQO
worldmags
worldmags
worldmags
January 2010 VOL. 119, NO. 1
NASA
On the cover: Astronauts on the Space Shuttle Atlantis photographed Hubble’s back end after its release into free flight May 19th.
THI S M O N TH ’ S S K Y
44
Northern Hemisphere’s Sky
AL S O IN THI S I S S U E
8
By Robert Naeye
By Fred Schaaf
47
January’s Sky at a Glance
49
Binocular Highlight
10 12
22 NASA Sets Its
Sights on the Sun The Solar Dynamics Observatory will reveal new details about how the Sun generates powerful storms that affect Earth. By Laura Layton & Dean Pesnell
50
Planetary Almanac
53
Sun, Moon, and Planets
57 61
F First Galaxies H Hubble has imaged the most distant galaxies yet, but to see the di first galaxies, astronomers need to go even deeper. By Jonathan P. Gardner
65
75, 50 & 25 Years Ago News Notes Mission Update By Jonathan McDowell
71
Going Deep By Ken Hewitt-White
Exploring the Moon By Charles A. Wood
24 Finding the COVER STORY
14 20
By Fred Schaaf
Letters By Leif J. Robinson
By Gary Seronik FE ATURE S
Spectrum
74
Telescope Workshop By Gary Seronik
Celestial Calendar By Alan MacRobert
84
Gallery
Deep-Sky Wonders
94
Focal Point
By Sue French
By Jacob Haqq-Misra & Seth D. Baum
32 July’s South
Pacific Eclipse On July 11th a lot of ocean and a few tiny bits of land will lie under a Moon-blackened Sun. By Fred Espenak & Jay Anderson
36 Hot Products for 2010
76 Spacecraft Imaging
for Amateurs An international community of space enthusiasts has become adept at processing and reinterpreting images from planetary spacecraft. By Emily Lakdawalla
6 worldmags
January 2010
sky & telescope
32
FRED & NAN ESPENAK
Our annual roundup of Hot Products highlights the most intriguing new astronomy gear on the market. By Dennis di Cicco
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.
worldmags
®
™
THE ALL NEW MEADE LT 6" THE WORLDS FINEST 6" TELESCOPE. PERIOD. The New LT 6" is a fully featured computer-controlled 6” Schmidt-Cassegrain telescope that sets a new high-performance standard for telescopes selling under $1,000. Its legendary Meade SC optics, along with precision worm gear drives, sturdy die-cast aluminum mount and robust steel tripod make this the ultimate platform for high-resolution visual observation and imaging. Simply put, the LT 6" is the ideal telescope any astronomer who demands superior optics, mechanics and computer control in a compact high-performance package.
Legendary Meade Optics The heart of any telescope is its optics. Meade Instruments offers you the finest 6" Schmidt-Cassegrain optics…period. Our advanced, proprietary processes deliver the highest quality professional grade optics available. For those who want more, we offer our patented Advanced ComaFree™ (ACF) system, delivering distortion free, sharp-as-a-tack optical resolution from edge to edge. Compare our Advanced Coma-Free system to Ritchey-Chrétien systems selling for thousands of dollars more. ACF’s quality will astound you.
AutoStar Computer Controller After a quick and easy alignment, the AutoStar computer controller guides the telescope to any of the over 30,000 objects in its comprehensive library, automatically. Don’t know what to see? Simply choose the “Tonight’s Best” tour, and AutoStar will show you the evenings finest objects. Planets, galaxies, nebulae, star clusters, double and variable stars, asteroids, comets, earth satellites, the International Space Station and more, are all included in the 30,000 plus database. AutoStar is updateable with downloads from our web site.
©2009 Meade Instruments Corporation. All rights reserved. Specification subject to change without notice. 30-09053
Precision Construction A rigid, die-cast aluminum mount solidly supports the optical tube in all sky orientations. Precision 4.875" diameter worm gears in both axes provides smooth Sidereal tracking of objects in the night sky. The stable, fully adjustable steel tripod delivers all the rigidity required in sensitive field applications.
worldmags
The Meade LT 6" delivers an astounding level of optical, mechanical and computer performance in a telescope — all for under $1,000. No other 6" telescope delivers this level of performance or value. For more information about the LT, or the entire family of Meade telescopes, or to find a dealer near you, visit www.meade.com.
MEADE LT 6" SC - $999 focal length: 1524mm / f10 MEADE LT 6" ACF - $1,099
Telescopes.com 800.303.5873 Optics Planet 800.504.5897
Woodland Hills 888.427.8766
OPT Telescopes 800.483.6287
Scope City Canada • Kahn Scopes 800.235.3344 800.580.7160
Astronomics 800.422.7876
worldmags
Robert Naeye Spectrum Founded in 1941 by Charles A. Federer, Jr. and Helen Spence Federer
The Essential Magazine of Astronomy
Is the James Webb Space Telescope a Good Thing? This month’s cover story discusses the recent discovery with
NA
SA
Hubble’s new camera of the farthest galaxies ever seen. Hubble brings us closer than ever to the birth of galaxies. But as the article also points out, we’ll need NASA’s James Webb Space Telescope to see this process in action. I must confess that I have mixed feelings about Webb. On the plus side, building a large infrared space telescope is the most practical way to accomplish this exciting science. Supercomputers can give us useful predictions about how the first galaxies formed, but astronomy is ultimately an observational science, so we need to see this process in action to fully understand it. In addition, Webb will teach us a tremendous amount about star and planet formation, and it will be able to image some nearby exoplanets. Webb could fo monitor transiting exoplanets, and perhaps spectroscopically detect chemimon cal constituents indicative of life. So it’s fair to say that Webb has the potential to make revolutionary discoveries on some of science’s most p profound questions. It will also take pretty pictures. pro But on the flip side, Webb will cost in the neighborhood of $5 Bu billion, surpassing any NASA space telescope other than Hubble. bi NASA’s astronomy budget will remain flat or decrease in the coming years, and as scientists and engineers construct this tenniscourt-size spacecraft, it consumes such a large fraction of the available astronomy budget that there’s little money to develop other missions. Moreover, Webb will be the largest and most complex space telescope ever built. As Jonathan Gardner explains in his article, Webb’s deployment involves a challenging series of maneuvers. There’s a lot that can go wrong, and the telescope will not be serviceable. Given NASA’s outstanding track record, and the high caliber of people on Webb’s science and engineering teams, the mission has a very high probability of success. But in this era of tight budgets, the last thing astronomers need is a $5 billion public relations fiasco. Building Webb at the expense of several cheaper missions is like putting most of astronomy’s eggs in one basket. Is this a good thing? I suppose it depends on your perspective. If you’re interested in the science questions that Webb will address, or if you’re an infrared astronomer, Webb is the greatest thing since the invention of the telescope. But if you’re an X-ray astronomer, or a physicist who wants to build a spacecraft array to detect gravitational waves from merging black holes, Webb is not your friend. As I experienced fi rst hand when I worked at Goddard Space Flight Center, NASA’s funding process often pits one group of scientists against another as they battle for precious resources in an era when there’s not enough money to go around. The professional astronomy community is not one big happy family, and neither is NASA.
Editor in Chief 8 worldmags
January 2010
sky & telescope
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 Contributing Editors Edwin L. Aguirre, 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, 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, Tony & Daphne Hallas ART & DESIGN
Design Director Patricia Gillis-Coppola Illustration Director Gregg Dinderman Illustrator Casey Reed PUBLISHING
VP / Publishing Director Joel Toner Advertising Sales Director Peter D. Hardy, Jr. Advertising Services Manager Lester J. Stockman VP, Production & Technology Derek W. Corson Production Manager Michael J. Rueckwald Production Coordinator Kristin N. Beaudoin IT Manager Denise Donnarumma VP / Consumer Marketing Dennis O’Brien Consumer Marketing Nekeya Dancy, Hannah di Cicco, Beth Dunham, Ellen Higgins, Jodi Lee, T.J. Montilli, Mike Valanzola Credit Manager Beatrice Kastner NEW TRACK MEDIA LLC
Chief Executive Officer Stephen J. Kent Executive Vice President / CFO Mark F. Arnett Corporate Controller Jordan Bohrer Office Administrator Laura Riggs Editorial Correspondence: Sky & Telescope, 90 Sherman St., Cambridge, MA
02140-3264, USA. Phone: 617-864-7360. Fax: 617-864-6117. E-mail: editors@ SkyandTelescope.com. Website: SkyandTelescope.com. Unsolicited proposals, manuscripts, photographs, and electronic images are welcome, but a stamped, self-addressed envelope must be provided to guarantee their return; see our guidelines for contributors at SkyandTelescope.com. Advertising Information: Peter D. Hardy, Jr., 617-864-7360, ext. 2133.
Fax: 617-864-6117. E-mail:
[email protected] Web: SkyandTelescope.com/advertising Customer Service: Magazine customer service and change-of-address
notices:
[email protected] Phone toll free U.S. and Canada: 800-253-0245. Outside the U.S. and Canada: 515-462-9286. Product customer service:
[email protected] Phone toll free: 888-253-0230. Subscription Rates: U.S. and possessions: $42.95 per year (12 issues);
Canada: $49.95 (including GST); all other countries: $61.95, by expedited delivery. All prices are in U.S. dollars. Newsstand and Retail Distribution: Curtis Circulation Co., 730 River Rd., New Milford, NJ 07646-3048, USA. Phone: 201-634-7400. No part of this publication may be reproduced by any mechanical, photographic, or electronic process, nor may it be stored in a retrieval system, transmitted, or otherwise copied (with the exception of one-time, noncommercial, personal use) without written permission from the publisher. For permission to make multiple photocopies of the same page or pages, contact the Copyright Clearance Center, 222 Rosewood Dr., Danvers, MA 01923, USA. Phone: 978-750-8400. Fax: 978-750-4470 Web: www.copyright.com. Specify ISSN 0037-6604. The following are registered trademarks of Sky & Telescope Media, LLC: Sky & Telescope and logo, Sky and Telescope, The Essential Magazine of Astronomy, Skyline, Sky Publications, SkyandTelescope.com, http://www.skypub.com/, SkyWatch, Scanning the Skies, Night Sky, and ESSCO.
worldmags
M51 image courtesy Greg Morgan. Alta U16M camera (4096 x 4096); RCOS 12.5” f/9 Ritchey-Chretien on Paramount ME; Astrodon filters.
Great Image! The Rest of the Story: For more than 15 years we’ve been refining our designs to meet the increasing needs of our most demanding customers. From the beginning, we’ve offered professional shutters from Vincent and Melles Griot and coated fused silica windows. Along the way, we’ve added deeper cooling to 75C below ambient, knife edge baffles, IR pre-flash, and high precision filter wheels unequaled in astronomy. With our lifetime guarantee on the inner chamber seal and two year parts and labor warranty, you can feel confident that you’re buying a time-tested platform from a company that stands behind their products. And with expert advice on your whole system from our Tim Puckett, you’ll be certain that you’re getting the best system for your needs.
worldmags
"Apogee has a well-deserved reputation of being a leader in the field of CCD imaging technologies. The quality of their products is second to none, and I have been extremely pleased with their service." Steve Cannistra 1020 Sundown Way, Ste 150 Roseville CA 95661 Tel: 916-218-7450 Fax: 916-218-7451 www.ccd.com ©2009 Apogee Instruments Inc. Alta is a registered trademark of Apogee Instruments Inc.
worldmags
Letters
If it were true that “energy flowing through a system tends to organize that system, into ever more complex and unpredictable forms,” (“The New Habitable Zones,” October issue, page 20) then we should be seeing piles of bricks and rubble spontaneously turning into houses all over the place. And ashes should be spontaneously turning into firewood. I belive that the reason we do not see such things is because the energy flowing through systems tends to disorganize them, not organize them (like explosions, for example). Furthermore, any engineer can tell you that inputting free energy into a system, as the Sun does to the Earth, increases the rate of disorganization; it does not reverse it. The Second Law of Thermo-
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. Published letters may be edited for clarity and brevity. Due to the volume of mail, not all letters can receive personal responses.
ON THE WEB S & T W E E K LY N E W S L E T T E R AND ASTROALERTS:
SkyandTelescope.com/newsletters
dynamics, therefore, does stand as an insurmountable obstacle to all theories of chemical evolution. John Tors Toronto, Ontario, Canada
[email protected] Editor’s reply: You’re confusing violations of the Second Law of Thermodynamics — bricks jumping up to form houses — with “emergent phenomena”: energy flowing through a system causing local organization at the expense of increased entropy elsewhere. You see this happening throughout nature — from complex turbulence appearing spontaneously in fluid flow, to life processes driven by sunlight increasing in complexity, over billions of years, to do things like build houses. — Alan MacRobert
Who makes their own optics anymore? I have been receiving Sky & Telescope since 1975, and I can’t help but miss the past abundance of articles on amateur telescope making and making your own optics. Doesn’t anyone make their own mirrors anymore? Sure, the new fancy telescopes from the major manufacturers have made great strides in price and quality, but there
G E T T I N G S TA R T E D I N A S T R O N O M Y :
SkyandTelescope.com/gettingstarted SKY-TOUR PODCASTS:
SkyandTelescope.com/podcasts L AT E S T A S T R O N O M Y N E W S :
SkyandTelescope.com/newsblog
A L M A N A C F O R Y O U R L O C AT I O N :
SkyandTelescope.com/almanac SELECTING A TELESCOPE:
SkyandTelescope.com/equipment/ basics
D A I LY S K Y - E V E N T D I A R Y :
SkyandTelescope.com/ataglance
DO-IT-YOURSELF PROJECTS
OFF-THE-WIRE STORIES:
SkyandTelescope.com/diy
SkyandTelescope.com/wires
SKY PUBLISHING CORPORATION
And God said, Let there be emergent phenomena!
Mirror-making with the Gainesville Boys’ Club in the early 1960s.
has got to be someone out there besides me who enjoys crafting something technical and precise just for the satisfaction! John McMichael Milwaukie, Oregon
[email protected] Editor’s reply: John is correct that the availability of high-quality, affordable commerical telescopes has impacted the amateur telescope making hobby. Nevertheless, S&T covers the topic in every issue with Gary Seronik’s Telescope Workshop column, and we welcome article proposals and submissions related to all aspects of telescope making. — Robert Naeye
WHAT D OE S THAT ME AN? BROWSE OUR ASTRO GLOSSARY
Trying to wrap your mind around astronomy terms? Looking to understand celestial coordinates? Confused about the Greek alphabet? Let us help you at SkyandTelescope.com/ Glossary. Learn the correct constellation names once and for all, and click the link to our Greek alphabet page directory while you’re there for more helpful information! S&T: GREGG DINDERMAN
10 worldmags
January 2010
sky & telescope
worldmags
worldmags
worldmags
Letters
2012 Paranoia? Montague, New Jersey (800) 266.9590
t: line a us on Visit
.high www
nt tscie poin
om ific.c
Introducing The 21mm Ethos From TeleVue Ethos 21mm Call for pricing FREE SHIPPING
After reading “The Great 2012 Scare” (November issue, page 22), I’m reminded of a quote sometimes attributed to Mark Twain: “Those who like to worry have the greatest selection in history.” Jonathan Hummel Ellicott City, Maryland
10" Dob Call for pricing FREE SHIPPING 12" Dob Call for pricing FREE SHIPPING
ETX-LS LIGHTSWITCH SCT - $1,299 FREE SHIPPING ACF - $1,499 FREE SHIPPING
worldmags
This mon ths fe ature d bra nds:
Gordon R. Lyell Johnston City, Illinois
Goodbye, IYA 2009!
For the Record
2009 brought us the International Year of Astronomy, marking 400 years since Galileo turned his telescopes to the Moon, planets, and stars. I’d like to recognize the amateurs and professionals who took the time to open observatories or set up equipment on sidewalks and in parks to give
✹ The two farthest supernovae recently discovered by Jeff Cooke and colleagues (October 2009, page 12) were found by stacking selected long exposures from the Canada-France-Hawaii Telescope’s Legacy Survey taken during good seeing, not from short exposures taken to freeze the seeing.
75, 50 & 25 Years Ago Sky Watcher 10" & 12" Dobsonians On Sale!
people a glimpse of our universe. As it becomes a memory, let’s remember IYA2009 with pride. Someday our current work, discoveries, and inventions will be celebrated as history by generations yet to come. Now that’s a nice thought.
January-February 1935 Important Nova “In the early evening of December 13 an English meteor observer J. P. M. Prentice . . . noted that between the stars Vega in Lyra and Gamma Draconis . . . there existed a star of naked eye brilliance where hitherto naught [but] starless sky had been the lot of the observer unpossessed of optical aid.” Decades later nova DQ Herculis would be instrumental in unlocking the secrets of these binary systems where one component transfers mass to a white dwarf. When this heated and compacted gas accumulates sufficiently, hydrogen fusion explosively occurs. January 1960 Planetarium Inventor “Perhaps no one person has done more for the popularization of astronomy than Walther Bauersfeld [1879-1959]. . . . “In 1919 he conceived the idea of the modern projection planetarium, designing and building the first instrument of this type. . . . More than 30 other Zeiss projectors have been erected. . . .” Very Irregular Stars “One most interesting feature of the Orion nebula is its
Leif J. Robinson large number of variable stars, a characteristic not discovered until the early years of this century. . . . “Many of these stars are noted for the rapidity of their light variations. . . .” My ego forces me to include this item; it was my first contribution to this magazine. January 1985 Digitized Planetarium “A new age in planetariums has arrived. . . . “Conventional star projectors cannot transport the viewer very far from the solar system, to see the heavens from other vantage points in space. Nor can they portray the changes wrought to constellations over time. . . . “With the advent of Digistar, a new planetarium projector that uses computer graphics, such displays are possible.” CCDs for All “For about two decades professional astronomers have used charge-coupled devices (CCD’s) as detectors. . . . “Undoubtedly, within a few years amateur astronomers will be using CCD’s as they now use photographic methods. A revolution has begun!” Christian Buil was prophetic. He built a linear CCD array and described it in S&T’s first such article aimed at amateurs.
worldmags
Introducing...
ATIK The ATIK Difference
ATIK Cameras
At ATIK we take pride in making fine CCD cameras for astronomy. They are packed with clever electronics to provide ultra low read noise and have useful features like fully regulated cooling. These make for extraordinarily sensitive cameras that enable you to capture beautiful, detailed images of deep sky objects.
Starting at 1/3” CCDs all the way up to 35mm format, ATIK covers the full range from entry level to professional research. Indeed ATIK cameras are used in observatories and laboratories throughout the world.
worldmags
ATIK
CAMERAS
ATIK Software
ATIK’s Maryland office (inset Warren Keller)
Every ATIK camera comes with our highly intuitive Capture software which includes focus assistance and imaging sequencing to make your time at the telescope as productive and rewarding as possible. Even with our use of cutting edge technology and software, ATIK cameras are easy to use, reliable, and affordable.
ATIK ATI IK Support We’re e pleased to announce the opening Frederick, open ning of our new office in Frederick Maryland, Maryyland, headed by world-renowned astrophotographer astrophotographer Warren Keller. We are committed c to delivering superior cameras and outstanding service as well. Now ATIK support is just a tollfree call away.
With ATIK there’s no compromise www ATIK USA com www.ATIK-USA.com
5108 Pegasus Court, Suite M, Frederick, MD 21704
877-284-5226
worldmags
News Notes For astronomy news as it breaks, see SkyandTelescope.com/newsblog. S ky
Sorting Out the Water on the Moon
ISRO / NASA / JPL / BROWN UNIV. / USGS
happen that way; the impact sprayed little visible debris, and what little data the probe and ground-based observatories collected was still being analyzed as this issue went to press. Just three weeks earlier, NASA had announced a total surprise: its Moon Mineralogy Mapper on India’s Chandrayaan-1 lunar orbiter detected H2O and OH (the hydroxyl radical) on the Moon’s daylit side, especially at high latitudes — contradicting more than a century of certitude that the Moon’s baking dayside is absolutely dry. Two other spacecraft confirm the discovery. You had to read further to find out that the “water” is only a molecule or two thick, bound to dust grains in the top millimeters of the lunar soil. Still, if you could sweep up a ton of the topmost dust, it might yield as much as a kilogram (liter) of water. That’s
Before Impact
If all the recent news concerning water on the Moon has left you confused, you’re not alone. Here’s the situation. Lunar geologists have long suspected that frost might accumulate over millions of years in permanently shadowed crater floors near the Moon’s poles. Water molecules arriving from rare comet-nucleus impacts on the Moon could freeze out onto this cold ground and stay there. (It’s as cold as 40 kelvins, scientists were recently surprised to find.) Loose water molecules might also be created over the ages from hydrogen in the solar wind reacting with oxygen atoms in surface rocks. And indeed, recent lunar orbiters have found clear evidence that the permanent shadowlands, and their surroundings, harbor hydrogen — most likely bound up in H2O, though at such a cold temperature it could also be in the form of frozen ammonia (NH3) or methane (CH4 ). On October 9th, the crash of NASA’s LCROSS mission into one of the shadowlands was supposed to settle the question spectacularly — by blasting up a huge plume of dust and water vapor for easy analysis, thereby paving the way for future lunar bases and settlements. It didn’t
Channel 8
After Impact
NASA / GSFC / UCLA
Channel 9
14 worldmags
January 2010
sky & telescope
Channel 7
Channel 6
drier that the driest desert on Earth — but still a potentially precious resource. The source may be protons (hydrogen nuclei) in the solar wind. Perhaps confusing some readers, the same stories in many media also discussed the fresh craterlets on Mars that are seen to expose widespread glaciers of pure ice, many meters thick, just under the Martian soil at high latitudes (S&T: July 2009, page 16). In the Moon Mineralogy Mapper image above, blue indicates the strongest water and hydroxyl spectral features at infrared wavelengths, red marks the iron-bearing mineral pyroxene, and green is reflected infrared sunlight. North is up. At left are temperature maps of the LCROSS impact area, taken in the midand far infrared by NASA’s Lunar Reconnaissance Orbiter, two hours before and 90 seconds after the impact. The fresh crater site shows as a warm pixel or two near bottom center.
worldmags
worldmags
worldmags
News Notes
Herschel’s First Show
thermal emission of very cold interstellar dust. The nebula is transparent at these wavelengths. Notice the bright points of star formation happening deep inside a few of the densest, coldest fi laments, almost like pearls on strings (inset). With a 3.5-meter aperture, Herschel is the largest space telescope yet flown.
ESA / SPIRE & PACS CONSORTIA (2)
As soon as the new Herschel Space Observatory was checked out and up to speed, the European Space Agency released a gorgeous mosaic of a very cold nebula as proof. One rendering of the picture, which spans 2° of sky near the Milky Way’s midline in Crux, is shown below.
It may look like other nebula images, but it’s not. It’s the first far-infrared/ submillimeter-wave image of the heavens taken with such clarity. Emission at 70 microns is shown as blue, 160 microns as green, and 250, 350, and 500 microns are combined as red. What we see here is mostly the weak
16 January 2010 worldmags
sky & telescope
worldmags
worldmags
Since
1975
Everything for the amateur astronomer
Orion SkyQuest XT8i Computerized IntelliScope ®
Orion StarShoot Deep Space Monochrome Imager III
Orion StarBlast 6 Astro Reflector Telescope
®
®
™
$1,499
™
$279
.95
.95
#9964
™
®
$529
.95
#27183
#52076
Step up to picture perfect optics
9
Orion Premium 190mm f/5.3 Mak-Newt Astrograph ®
$1,399
Orion StarShoot Planetary Imager & AutoGuider ®
$349
.95
#9978
Upping the “wow” factor of an already impressive design
™
.95
#52079
Happy Holidays from Orion! Check out the Orion page on Facebook www.facebook.com/oriontelescopes
Orion Nautilus Motorized 7x1.25" Filter Wheel ®
™
$429
.95
#5527
OrionTelescopes.com
Orion SkyQuest XX14i IntelliScope Truss Dobsonian ®
$1,799
.95
™
®
#9791
Orders: (800) 447-1001 Customer Service: (800) 676-1343
prices subject to change without notice
worldmags
News Notes
ALMA Progressing
Saturn’s New King Ring
Speaking of far-infrared and millimeter waves: What’s about to be the world’s most powerful imaging telescope of any kind? You could make a good case that it’s ALMA, the Atacama Large Millimeter/ submillimeter Array, now under construction on the 16,000-foot (5,000-meter) Chajnantor plateau in the Chilean Andes. ALMA will consist of at least 66 dishes, 12 and 7 meters in diameter, spread over distances as great as 18.5 kilometers. They will be tightly integrated to form one huge, diffraction-limited synthetic
Phoebe is the black sheep of Saturn’s major moons. It’s the farthest out, and it orbits backward compared to the rest. It’s probably not an original member of the Saturnian family but a Kuiper Belt object that was captured ages ago. Just 135 miles (215 km) across, this oddball now has new claim to fame: Saturn’s biggest ring. Astronomers hunting for trace rings with NASA’s Spitzer Space Telescope find that Phoebe orbits within a gigantic, but very tenuous, dust ring vastly larger than those previously known.
Saturn
Like the orbit of Phoebe, it’s tipped 27° to the plane of the inner Saturnian system. A mere 1 cubic kilometer of Phoebe dust, ejected by impacts, could account for the entire big ring. Planetologists suspect that this dust has something to do with why Iapetus, Saturn’s next moon in, is very dark on its leading hemisphere.
Messenger’s Third Look at Mercury
NASA / JHU-APL / CARNEGIE INST. OF WASHINGTON
ESO
aperture working at wavelengths from 350 microns to 9 millimeters. Its typical image resolution will be about 0.02 arcsecond, ten times sharper than Hubble. At left, a specially built transporter carries the first 12-meter, 100-ton dish to its docking site on the plateau, which is above about half of Earth’s atmosphere and nearly all of its water vapor. The ALMA team plans to link three antennas to form an interferometer by early 2010 and begin scientific observations with several more dishes in the second half of 2011. The full array could be finished in 2012.
NASA’s Messenger probe made its third flyby of Mercury on September 29th, revealing more lands never before seen. Among the sights: impact craters with big, irregular depressions or pits on their floors. The pits appear to have formed by the collapse of subsurface magma chambers. If so, they are more evidence of volcanism at work on the innermost planet. An example is the elongated beanshaped depression near the middle of the large crater above. Another possible example is centered in the large crater below it. When Messenger next comes to Mercury, on March 18, 2011, it will fire a braking rocket, slip into orbit, and finally begin an intensive year-long study of the planet.
SOURCE: NASA / JPL, S&T ILLUSTRATION: CASEY REED
Apophis Turns Less Menacing
Phoebe
Titan
Iapetus
The world’s biggest asteroid scare so far came during Christmas week of 2004. Early orbit calculations showed the recently discovered asteroid 99942 Apophis (then called 2004 MN4) having a 1-in-37 chance of hitting Earth on April 13, 2029. About
News Note stories are presented in greater depth, with links, at SkyandTelescope.com; search for the keyword SkyTelJan10.
18 worldmags
January 2010
sky & telescope
worldmags
worldmags
worldmags
900 feet (300 meters) wide, Apophis would arrive with the energy of several hundred megatons of TNT, roughly 10 times more energy than the largest thermonuclear bomb ever tested. But as soon as its positions were measured over a longer time span (thanks to pre-discovery images being located), an impact in 2029 was ruled out completely. Nevertheless, a 1-in-45,000 chance remained for April 13, 2036. Now, with ever longer orbital tracking, that chance has been downgraded to 1 in 250,000. Another impact possibility has shown up for April 13, 2068, but at only the 1-in-300,000 level. Do mark your calendar for April 13, 2029, however. Apophis will miss us by only three Earth diameters, and will be visible to the unaided eye creeping across the night sky as bright as 3rd magnitude.
Mission Update
Surviving the Late Heavy Bombardment Conventional wisdom has been that the solar system’s “Late Heavy Bombardment,” which pummeled all the inner planets and gave the Moon its biggest impact scars, must have sterilized Earth. The bombardment ended 3.9 billion years ago, so biologists assume that the ancestors of all living things today originated after that. Trace evidence of life exists from 3.83 billion years ago — which implies that life started as soon as it possibly could. That, in turn, would suggest that life arises quickly and easily on suitable planets everywhere. But a new study finds that bacteria several kilometers deep in Earth’s crust (where some microbes live today) could survive even multiple blows severe enough
Jonathan McDowell
Fobos-Grunt to Mars: Delayed
PHOBOS: HIRISE / MRO / LPL / NASA. SPACECRAFT: NPO LAVOCHKIN.
Russian space scientists have a long and mostly bitter history with the Red Planet. The occasional technical success (in 1971 Mars2 was the first human artifact to reach the planet’s surface) has been overshadowed by repeated failures. Most recently, in 1996 Russia’s first post-Soviet Mars p probe crashed in Bolivia soon after takeoff . off Undaunted, Russia’s Institute of Space
Research began planning an even more ambitious mission, Fobos-Grunt (“PhobosSample”). The U.S. has long discussed, but never funded, a sample return from the surface of Mars. Anticipating the Augustine Commission’s “stay out of gravity wells” recommendation, Fobos-Grunt would instead return a soil sample from Mars’s largest moon. Russia insisted that the mission would fly R during the October 2009 Mars-launch window. dur But no one was surprised when in September Bu word came at the last minute that Foboswo Grunt would not launch until 2011. In fact, G fundamental design questions remain about fu the type of soil sampler to be used.
Yinghuo-1 to Mars: Delayed Yi Also delayed is Fobos-Grunt’s Chinese passenger, a microsatellite to study the Martian environment. Hitching a ride to Mars on the Russian spacecraft, the 120kg Yinghuo-1 would be dropped off in an elliptical orbit. As it passes behind the limb of Mars as seen from Fobos-Grunt, its radio signals will allow scientists to measure Martian ionospheric conditions.
20 worldmags
January 2010
sky & telescope
OLEG ABRAMOV / UNIV. OF COLORADO
News Notes
to boil off all of Earth’s oceans. These microbes could later recolonize the surface when times improved. If so, today’s life could have originated anytime in Earth’s first 800 million years. If life didn’t necessarily spring into being as soon as conditions allowed, this weakens the case that life probably gets going easily on every good planet. The image above is from a temperature simulation of Earth during the bombardment era. ✦
Piggybacking to Venus The Yinghou-1 mission was to be the first of a new generation of small, cheap spacecraft flying as passengers on expensive planetary missions, but it now looks to be scooped by two Japanese probes. When Japan’s Venus Climate Orbiter takes off this May (S&T: November 2009, page 16), the second stage of its H-IIA rocket will jettison two small experiments into solar orbit. IKAROS (Interplanetary Kite-Craft Accelerated by Radiation of the Sun) is a 20-meter-wide solar sail covered with photovoltaic cells. The sail will spend several months in a technology demonstration, generating power and using solar radiation pressure to change its orbit. UNITEC-1, the second passenger, is a 15-kg, 30-cm cube developed by a group of Japanese universities to test on-board computers in the interplanetary radiation environment, as well as deep-space communications and tracking. Flush with the success of a plethora of student-built 1-kg ‘cubesats’ in low Earth orbit, other university groups are also looking to interplanetary space for the first time. Contributing editor Jonathan McDowell covers more missions at Jonathan’s Space Report: www.planet4589.org.
worldmags
*SEE WEBSITE FOR OTHER OFFERS AND COMPLETE DETAILS Good through 1/31/10 Limited to stock in-hand.
HOLIDAY ! REBATES
Color corrected optics.
WOW!
$155
WOW!
$170 SW 80AR-EQ2
Easy to use red dot location pointer. All models.
90AR-AZ3 130N-EQ2
WOW!
$79
WOW!
$195 70AR-AZ2
Two super Plössl eyepieces 1/4” diameter.
Deluxe flex steel cable controls most models.
Is this to be your first telescope? Want a great experience? You just found it! Quality optics, superb Plössl eyepieces, rigid mount & tripod, and more! Trust Sky-Watcher for best in class performance!
RETAIL AFTER HOLIDAY INSTANT REBATES* SW 70AR-AZ2 . . . . . $79 – SAVE $16 SW 80AR-EQ2 . . . . $155 – SAVE $20
HIGH PERFORMANCE EYEPIECES
SW 90AR-AZ3 . . . . $170 – SAVE $20 SW 130N-EQ2 . . . . $195 – SAVE $40
COOL BACKPACK OBSERVATORY! All Components Fit in Stylish Backpack
HIGH PERFORMANCE DOESN’T HAVE TO COST AN ARM AND A LEG. SKY-WATCHER EYEPIECES DELIVER PREMIUM QUALITY AND AMAZING VALUE !
Model Shown: MAK-90
RETAIL AFTER HOLIDAY INSTANT REBATES* SW MAK-90 Mulit-Mount . . $295 - SAVE $55
SAVE $20 TO $28
2” Series – 35mm
2” Series
Super Plössl Series – 32mm
Save
Wide Angle Series – 20mm
Super Plössl Series 52º AFV
Save
IN INSTANT RE BATE ON SK Y-WATCH S* ER EYEPIECES Wide Angle Series 66º AFV
at the Touch of a Computer Keypad Model Shown: SW 102AR-AZ SynScan Computer Controller
Save
42mm, 52º AFV . . . . . . . . . .$59 $28 35mm, 56º AFV . . . . . . . . . .$49 $28 28mm, 56º AFV . . . . . . . . . .$49 $28
10mm, 6.3mm, 7.5mm. . . . .$27 $20 17mm, 20mm, 26mm . . . . .$27 $20 32mm, 40mm . . . . . . . . . . .$34 $23
20mm, 15mm . . . . . . . . . . .$34 $23 9mm, 6mm . . . . . . . . . . . . .$34 $23
Affordable Sky-Watcher 2” eyepieces are an exceptional value. Precision polished lenses with multi-coatings offer long eye-relief and a modestly wide apparent field of view.
The Sky-Watcher Plössls offer near edgeto-edge sharpness, blackened barrel interiors, multi-coated optics, rubber grips and eyecups, wide apparent field of view, and modestly long eye-relief.
Ultra Wide Angle Sky-Watcher eyepieces offer a generous 66º apparent field of view. These are high quality eyepieces sure to be prized possessions in your eyepiece collection.
worldmags
LIGHTCHARIOT: Find 4,000 Objects
RETAIL AFTER HOLIDAY INSTANT REBATES* 102AR-AZ . . . . . . .$395 - SAVE $30 130N-AZ . . . . . . . .$340 - SAVE $55 80AR-AZ. . . . . . . . $295
SCOPE CITY OPT ADORAMA OPTICS PLANET ASTRONOMICS SEE OUR WEBSITE 800-235-3344 800-483-6287 800-223-2500 800-504-5897 800-422-7876 FOR MORE DEALERS WWW.SKYWATCHERUSA.COM s 888.880.0485 s 2935 COLUMBIA STREET s TORRANCE s CA 90503
worldmags
Peering into the Sun
NASA
SETS ITS SIGHTS ON THE
SUN
laura layton & dean pesnell The Solar Dynamics Observatory will reveal new details about how the Sun generates powerful storms that affect Earth. SOHO / NASA / ESA
THE S UN
PROFOUNDLY INFLUENCES influences Earth and our technology. When our nearest star produces flares and coronal mass ejections — sudden massive eruptions of gas and solar material with embedded magnetic fields — the solar wind can send swarms of particles that slam into Earth’s magnetic field. The effects of this space weather range from beautiful aurorae
22 worldmags
January 2010
sky & telescope
to more dramatic and deadly power outages, interrupted satellite communications, and harmful radiation. NASA’s newest Sun-focused mission — the Solar Dynamics Observatory (SDO) — will study and investigate changes in solar variability and their effects on Earth. SDO is the first mission of NASA’s Living With a Star Program. The spacecraft is scheduled to launch
worldmags
Extreme ultraviolet Variability Experiment (EVE)
Atmosphere Imaging Assembly (AIA) Solar arrays
Helioseismic and Magnetic Imager (HMI) High-gain antennas
S&T: CASEY REED
Solar Dynamics Observatory
in early 2010 from Cape Canaveral, Florida. An Atlas V rocket will lift the 6,800-pound (3,100-kg) spacecraft into an inclined, geosynchronous orbit around Earth so it can continuously watch both the Sun and its dedicated ground station near Las Cruces, New Mexico. The spacecraft will study small-scale changes in the Sun’s atmosphere in many wavelengths simultaneously and observe how its powerful magnetic field is generated and structured. Scientists will also investigate how stored magnetic energy is converted and released in the form of the solar wind and energetic particles, and how these processes influence changes in solar energy output. We anticipate the spacecraft’s primary science mission to last 5 years, but it has enough fuel for 10 years. The $850 million mission will collect a staggering amount of data. SDO will take full-disk solar images every second with 10 times the resolution of high-definition television. At 4,096 by 4,096 pixels, SDO images will have the visual quality of an IMAX movie. Three instruments will collect about 1.5 terabytes of data per day, about the equivalent of downloading 500,000 songs daily. The Atmospheric Imaging Assembly (AIA), a four-telescope array, will image the outer layer of the Sun’s corona in multiple wavelengths nearly simultaneously. AIA will image the Sun in 10 wavelengths every 10 seconds. The images will span at least 1.3 solar diameters at a resolution of about one arcsecond (a patch of the Sun about the size of New Mexico). AIA data will help scientists understand how the Sun’s changing magnetic fields release the energy that heats the corona and triggers solar flares.
The Extreme ultraviolet Variability Experiment (EVE) will measure variations in the Sun’s extreme-ultraviolet spectral irradiance over multiple time spans. The Helioseismic and Magnetic Imager (HMI) will look inside the Sun and map the plasma flows that generate the Sun’s magnetic fields. HMI will use the sound waves moving across the Sun to build up images of the solar interior. HMI will also measure the strength and direction of magnetic fields emerging from the photosphere. HMI data will give insight into the mechanisms that cause the Sun’s 11-year activity cycle and reveal how magnetic fields become concentrated in the areas around sunspots. Combined, the SDO instruments will probe the Sun’s magnetic field and its terrestrial influences. Scientists will use SDO data to understand what causes a coronal loop to arch above the Sun, a solar flare to erupt, and a coronal mass ejection to suddenly blast millions of tons of material toward Earth. Learning more about these forms of space weather will help better protect our access to electricity, satellites in space, and human explorers who venture beyond Earth’s atmosphere. ✦ Laura Layton is a science writer at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. Dean Pesnell is the SDO project scientist, and is also based at NASA Goddard.
◀ SOLAR ERUPTION This composite image from the SOHO spacecraft’s LASCO and EIT instruments shows a coronal mass ejection (CME) that contains millions of tons of material. SDO’s AIA instrument lacks a coronagraph for blocking out the Sun itself, but it will directly image CMEs more frequently, at more wavelengths, and at higher resolution.
IN GODDARD CLEAN ROOM A technician works on the Solar Dynamics Observatory. The craft spans 14.8 feet (4.5 meters) along the Sun-pointing axis and weighs 6,800 pounds.
worldmags
NASA / SDO
▶ SDO
Sk yandTelescope.com
January 2010
23
worldmags
Seeing the Universe Take Shape
Finding the First jonathan p. gardner
Hubble has imaged the most distant galaxies yet,
NASA / ESA / GARTH ILLINGWORTH / RYCHARD BOUWENS, ET AL.
AUTHOR PHOTO: NASA / BILL HRYBYK
N
24 January 2010 worldmags
sky & telescope
worldmags
Galaxies but to see the first galaxies, astronomers need to go even deeper.
STAR-FORMATION HISTORY Right: A variety of surveys have enabled astronomers to plot the rise and fall of star formation dating back to redshift 8. Given the fact that mature stars existed at redshift 8, the first stars and galaxies must have formed even earlier, during a mysterious epoch that the James Webb Space Telescope is being built to explore.
worldmags
Age of universe (billions of years) 0
2
4
6
8
10
12
30 10 SOURCE: JONATHAN GARDNER
GOING ULTRA-DEEP Left: By using Hubble to stare at a single field, astronomers bore a “tunnel” through space and time to see galaxies in the early universe. The latest Hubble Ultra-Deep Field, which shows the same patch of sky as an earlier Ultra-Deep Field, includes data taken by the new WFC3 camera. By going further into the infrared, this image reveals 5 galaxies around redshift 8.5.
southern constellation Fornax for more than 500 hours of exposure time. The resulting Hubble Ultra-Deep Field could see the faintest and most distant galaxies that the telescope is capable of viewing in visible light. The more recent WFC3 observations were made over the course of about 48 hours in the same field, and they extend the wavelength coverage into the near-infrared. From the Ultra-Deep Field and other galaxy surveys, astronomers have built up a history of star formation. The peak occurred about 10 billion years ago, about a fourth of the universe’s current age, when galaxies were churning out stars at about 15 times the rate today. As we go further back in time to when the very first stars and galaxies formed, the average star-formation rate should drop to zero. But the new WFC3 observations reveal a star-formation rate that remains comparable to that of galaxies today. Despite Hubble’s impressive technical accomplishment, we have to go even deeper to observe how the universe’s first galaxies formed. There are two problems: the first galaxies are too faint for Hubble or any existing telescope, and cosmic expansion has redshifted their visible light even beyond Hubble’s new near-infrared capability. To detect them,
Star formation rate
In May 2009, astronauts installed two new cameras in the Hubble Space Telescope, making Hubble more powerful than ever. The new Wide-Field Camera 3 (WFC3) increases Hubble’s sensitivity and field of view at nearinfrared wavelengths, improving its ability to search for distant galaxies by as much as a factor of 20. It didn’t take long for WFC3 to make its mark. Garth Illingworth, Rychard Bouwens (both at the University of California, Santa Cruz), and their colleagues recently used WFC3 to find 5 galaxies, circled in the image to the left, that are more distant than any seen before, pushing our knowledge of galaxy evolution back to just 600 million years after the Big Bang (a redshift of about 8.5). These early galaxies are about the same distance as gamma-ray burst 090423, which recently established the record for most-distant known object (S&T: September 2009, page 26). But we’re interested in more than just breaking records. We want to understand how galaxies formed, and how they built themselves up into the giant congregations that we see today. Astronomers study distant galaxies by taking long exposures in relatively empty fields. In 2004 astronomers pointed the Hubble Space Telescope at a small field in the
ALL SPACECRAFT ILLUSTRATIONS: S&T: CASEY REED
3 1
0.3 8 4
2
1
0.5 0.3
0
Redshift
Sk yandTelescope.com
January 2010
25
worldmags
Seeing the Universe Take Shape
Near Infrared (Hubble)
Infrared (Spitzer)
Combined Visible–Infrared (Hubble & Spitzer)
NASA / ESA / JPL-CALTECH / BAHRAM MOBASHER
Visible (Hubble)
DISTANT GALAXY The Hubble and Spitzer space telescopes teamed up to detect one of the most distant galaxies ever seen (circled), at a redshift of about 6.5. The relatively massive galaxy becomes increasingly brighter in near-infrared and infrared wavelengths, an indication that its stellar population is surprisingly mature for a galaxy that existed only 850 million years after the Big Bang. This discovery suggests that the galaxy and many of its stars formed hundreds of millions of years earlier.
NASA is building the James Webb Space Telescope for launch around 2014. Webb will have a 6.5-meter primary mirror, much bigger than Hubble’s 2.4-meter primary, and Webb will be optimized for infrared observations to see the highly redshifted first galaxies.
Building Galaxies
NASA / ESA / NORBERT PIRZKAL
After the Big Bang, the universe was fi lled with hydrogen and helium, expanding and cooling and responding to
26 worldmags
January 2010
4.00
sky & telescope
4.88
the gravity of growing clumps of dark matter. Theory says that large stars formed first, when the universe was about 100 million years old, a redshift of 30 (S&T: May 2006, page 30). These stars quickly exploded as supernovae, whose winds blew all the gas out of the relatively small dark-matter clumps, disrupting any chance that nearby stars would form. At about 250 million years (redshift 16), clouds of gas began to collapse to form stars very rapidly, in a wide range of sizes. The first galaxies were born.
4.90
5.42
The early galaxies seen in the Hubble Ultra-Deep Field were small by today’s standards, not much bigger than globular clusters. They look like a mess: compact, blobby aggregations that resemble train wrecks. Their masses are difficult to measure, but they are all clearly smaller than our Milky Way. But these galaxies evolved into the regular galaxies that make up the Hubble Sequence. Galaxies build up through hierarchical merging. Relatively nearby galaxies appear to be interacting gravitationally, producing tidal tails, rings, and other structures that indicate recent collisions. When two large spiral galaxies collide in supercomputer simulations that trace the gravitational interactions of hundreds of millions of stars, they go through stages that look like observed merging galaxies (S&T: October 2006, page 30). The final result of these simulations is an elliptical galaxy. Spiral and elliptical galaxies are built up over cosmic history, as larger and larger galaxies merge. Spirals become ellipticals in major mergers; ellipticals merge in the centers of galaxy clusters to become central dominant galaxies, such as M87 in the Virgo Cluster. By this process, the very small galaxies that first formed in the early universe built up into the giant congregations we see today. For example, hundreds of small galaxies merged to form galaxies such as our Milky Way. The earliest galaxies are not only faint because they are very distant; they are also ultra-faint because of their diminutive size.
Techniques for Going Deep Computer models give us good ideas for how galaxy mergers occurred, but we’d like to see how this process occurred in the early universe. One way to accomplish this task is to use a technique predicted by Einstein’s general theory of relativity. The dark matter in a cluster of galaxies can act as a gravitational lens, focusing the light from background objects and boosting their observed brightness by a factor of 10 or more. Astronomers have used this technique to find a few faint and very distant galaxies, but the magnified area is small, so it’s difficult to obtain a statistical sample. The Hubble Ultra-Deep Field was taken through 4 wide visible-light filters, with the recent WFC3 addition taken through 3 near-infrared filters. For the most distant
worldmags
5.76
ROBERT GENDLER
worldmags
COLLIDING GALAXIES The famous colliding galaxies of the Antennae (NGC 4038 and 4039) allow astronomers to study the same merger processes in the relatively local universe that occurred much more frequently in the early universe. Note the extended tidal tails from gravitational interactions. The two galaxies might eventually merge into a giant elliptical galaxy.
galaxies, cosmic expansion has redshifted their ultraviolet output into the near-infrared. Intergalactic gas absorbs light emitted at even shorter ultraviolet wavelengths, so even-higher-redshift galaxies successively drop out of the images. By observing how galaxies disappear in these deep images, astronomers can measure the galaxies’ redshifts. But at the highest redshifts, when the emitted ultraviolet light is redshifted beyond the near-infrared part of the spectrum, Hubble can’t see the galaxies at all, not even when using a gravitational lens. Infrared light is heat radiation, so a telescope must be very cold to see it at all. Otherwise, doing infrared astronomy with a warm telescope is like doing visiblelight astronomy with a telescope full of light bulbs; the telescope itself outshines what you’re trying to observe. Heaters keep Hubble at room temperature, about 25°C,
TRAIN WRECKS These faint, fuzzy blobs in the Hubble Ultra-Deep Field might not seem like much, but they’re the building blocks of today’s galaxies. Each blob is 1/100 to 1/1,000 the size of our Milky Way, but blazes with the light of millions of young stars. The tadpole-like tails in three of the galaxies indicate that they’re merging with neighboring galaxies. The numbers refer to each galaxy’s redshift.
For more on the James Webb Space Telescope, visit www.jwst.nasa.gov.
Sk yandTelescope.com
January 2010
27
worldmags
Seeing the Universe Take Shape
tion of stars, but contained a substantial population of older stars, possibly as much as 400 or 500 million years old. Some of these galaxies must have formed when the universe was much less than 1 billion years old, and their ultraviolet light was redshifted well into the infrared, beyond Hubble’s reach. Although Spitzer was cold enough to detect infrared light, its primary mirror is just 85 centimeters. This small size limits Spitzer’s sensitivity to faint galaxies in two ways. First, it’s simply not collecting enough light to see galaxies fainter than those in the Ultra-Deep Field. Second, the telescope’s resolution depends on the ratio of the wavelength divided by the aperture. With longer wavelengths and a smaller mirror, the faintest galaxies in Spitzer images overlap one another.
Primary Mirror Sizes
Hubble (2.4 meters)
Webb (6.5 meters)
The James Webb Space Telescope
Spitzer (0.85 meter)
The James Webb Space Telescope will be colder than Hubble and larger than Spitzer. Sitting behind a giant sunshield, Webb will radiate its heat into deep space and passively cool to beyond –225°C. Its large mirror and cold temperature translates into the infrared sensitivity needed to detect the first galaxies that formed 250 to 400 million years after the Big Bang. There are major technological hurdles in building Webb. As Hubble goes in and out of sunlight, heaters keep the telescope at a constant temperature. NASA launched Spitzer into a solar drift-away orbit, orbiting the Sun behind Earth and drifting 10 million miles from Earth each year. By moving away from us, Spitzer can use a shield to prevent sunlight from heating the telescope. Webb will also hide behind a sunshield, one as big as a tennis court! NASA will launch Webb into a special orbit around the second Lagrangian point in the Earth–Sun system, called L 2, about 1 million miles from Earth. Being more distant from the Sun than Earth, the observatory would normally take longer than one year to orbit the Sun, and slowly drift away, like Spitzer. But at L2, Earth’s gravity will pull on Webb just enough to keep it in synch, so the Sun, Earth, and the L 2 point are always in a line. Webb’s sunshield will not only protect the telescope from the Sun’s heat, but also from scattered light from the sunlit portions of the Earth and Moon. The telescope will always be overhead at midnight each night. The largest launch rockets are 5 meters wide, so
in order to maintain its stability as it goes in and out of sunlight in low-Earth orbit. Although the telescope has some near-infrared capability, its temperature limits its sensitivity at the longest wavelengths. In 2003 NASA launched the Spitzer Space Telescope, an infrared-sensitive telescope that uses liquid helium to stay colder than –262°C, or only 11°C above absolute zero. Spitzer provides the infrared sensitivity that Hubble lacks. When astronomers pointed Spitzer at the Ultra-Deep Field, they were surprised to discover that some of the most distant galaxies were shining brightly in the infrared. When galaxies first form stars, the largest stars dominate their light. These stars, 30 to 50 solar masses, are very hot and put out most of their radiation in the ultraviolet. But burning brightly has its price, and the most massive stars are also the shortest lived. After just a few million years, they run out of hydrogen fuel and explode as supernovae. Smaller stars, like our Sun, come to dominate the light output of the galaxy. These smaller stars are cooler and put out most of their energy as visible or near-infrared light, with much less ultraviolet. For the distant galaxies in the Ultra-Deep Field, their emitted ultraviolet light is redshifted to the edge of the visible-light band, and their emitted visible light is redshifted into the infrared. The Spitzer detections showed that these galaxies were not forming their fi rst genera-
VISIBLE
S&T: CASEY REED (2)
ULTRAVIOLET
NEAR INFRARED
MID INFRARED
Hubble Spitzer Webb 0.1
0.6
2.5
3
Wavelength (microns)
28 January 2010 worldmags
FAR INFRARED
sky & telescope
28.5
180
1,000
worldmags
another technological development is needed to enable Webb to deploy its 6.5-meter primary mirror in space. The mirror consists of 18 segments, each with an independently controllable position. The mirror will stand on its edge in the rocket and the three segments on each side will be folded back like the leaves of a tabletop. The sunshield is folded around the mirror. After launch, the solar panels will unfurl to supply the observatory with power. The communications antenna will point toward Earth, and a deployed isolation tower will separate the telescope from the spacecraft. The sunshield will then unfold, and its five layers will separate. The sunshield has five layers for two reasons. First, heat can escape between the layers. Second, if it’s punctured by a micrometeorite, the holes will be unlikely to line up in such a way that sunlight will scatter onto the primary mirror. Finally, the secondary mirror will be supported on a three-legged spider, and the leaves of the primary mirror will be folded out. Once everything has been deployed, the telescope will be pointed at a bright star, and the 18 petals of the primary mirror will be brought to a common focus. All this new technology comes at a price. The total lifecycle cost of Webb will be about $5 billion for NASA, plus additional contributions from Europe and Canada. Late 1990s estimates ranged from $500 million to $1 billion for construction costs only, which did not include technology development, design work, or post-launch operations. But even the cost of the construction phase has more than doubled. Much of this increase is due to the rigorous testing program that will virtually ensure that Webb will work when it reaches its proper orbit. The current cost of Webb is comparable to the cost of Hubble’s construction, once corrected for inflation and changes in accounting procedures. Following an independent review, the Webb
worldmags
4h
2h
3h
1h
PSC
+10°
G A
TAURUS
D CETUS
Star magnitudes
D 2 3 4 5 6
0°
H
E
–10°
G ERIDANUS T4 HUDF
B
T3
–20°
A B –30°
FORNAX
SCULPTOR
Q
–40°
DEEP AND DARK The Hubble Ultra-Deep Field lies in the dim constellation Fornax, tucked into a dark loop of Eridanus. The field is centered on right ascension 3h 32m 40.0s, declination –27º 48´ 00˝. Only 3 arcminutes on a side, it spans as much sky as a grain of sand held at arm’s length. The yellow cross marks the spot; the actual field at this scale is microscopic.
Lagrangian Points L5
L 2 Earth
Moon
L3
L1
Sun
L4 Not to scale
S&T: CASEY REED
Webb
James Webb The James Webb Space Telescope is named for NASA’s second administrator. James Webb’s term (1961–1968) spanned the presidencies of John F. Kennedy and Lyndon Johnson, a period of rapid growth for NASA that witnessed the successful completion of the Mercury and Gemini manned spaceflight programs, and the early years of Apollo. Many successful spacescience missions were also developed or flown during Webb’s tenure.
Sk yandTelescope.com
January 2010
29
worldmags
Seeing the Universe Take Shape
THE NEXT GENERATION OF
ASTRONOMY
CAMERAS
MANUFACTURED TO INDUSTRIAL STANDARDS
8
project recently transitioned to its formal “implementation” phase, and NASA certified the budget and schedule to Congress.
1/4“ CCD (60FPS) 1/3“ CCD (30FPS) 1/2“ CCD (15FPS)
The James Webb Space Telescope will be the successor to Hubble and Spitzer. Like Hubble, it represents a major international collaboration, with contributions from the European and Canadian space agencies. Although initially designed to detect the first galaxies, it will be a general-purpose observatory able to address nearly every aspect of astronomy. Stars and planets form in dense clouds of gas and dust in a complex interaction between gravity, angular momentum, gas pressure, and magnetic fields. Dust blocks much of the ultraviolet and visible light from escaping the cloud, and stellar cradles such as M16 appear as beautiful but opaque nebulae. Infrared light penetrates the dust to reveal the forming stars. At a later stage, the star forms a protoplanetary disk; the star heats the disk so that it glows in the infrared. By providing high-resolution, high-sensitivity images in the infrared, Webb will be a powerful tool for investigating the formation of stars and their planetary systems. Like Hubble and Spitzer, Webb will be used by thousands of astronomers from
WWW.ASTRONOMYCAMERAS.COM THE
IMAGINGSOURCE ASTRONOMY CAMERAS
30 January 2010 worldmags
sky & telescope
Jonathan P. Gardner is Chief of the Observational Cosmology Laboratory at NASA’s Goddard Space Flight Center.
HUBBLE
SPITZER
JAMES WEBB
Low-Earth Orbit
Heliocentric Earth-Trailing
Sun–Earth L 2
13.3 meters
4 meters
22 meters
11,110 kilograms
865 kilograms
6,530 kilograms
300 kelvins
5.5 kelvins*
35 to 55 kelvins
1990
2003
2014 (scheduled)
Space Shuttle Discovery
Delta II
Ariane V
57.6 meters
10.2 meters
131.4 meters
No. of instruments
5**
3*
4
Angular resolution
0.043 arcsec at 0.5 microns (μ)
1.6 arcsec at 6.5 μ
0.063 arcsec at 2.0 μ
Orbit Length Mass Mirror temperature
Launch vehicle Focal length
CONTROL SOFTWARE & DRIVERS
around the world, and it will deliver beautiful pictures. And just as we saw with Webb’s predecessors, its most important discoveries are likely to be things we haven’t even thought of yet. ✦
NASA Space Telescopes Compared
Launch date
USB CONNECTORS FIREWIRE CONNECTORS
Redshift is a measure of how much an object’s light is shifted toward the red end of the spectrum. Redshifts for objects within our galaxy are generally due to motion away from Earth. But redshifts for distant galaxies result from cosmic expansion, with the higher the redshift, the farther the galaxy. We see distant galaxies as they existed long ago, and the expanding universe has grown in size since then. So astronomers often refer to distances to extragalactic objects in terms of redshift rather than light-years. Astronomers sometimes use lookback time, or time elapsed since the Big Bang, which took place about 13.7 billion years ago.
A General-Purpose Observatory
NOW IN GigE MONOCHROME COLOR WITH & WITHOUT IR CUT
High Redshift = Large Distance
* Since the depletion of coolant on May 19, 2009, the Spitzer primary mirror has warmed up to about 30 kelvins, and only 1 instrument is working. ** Hubble currently has 5 science intruments, plus the Fine Guidance Sensor, which is sometimes used for astrometric science. Hubble has had 12 total instruments over its liftime, including those that have been replaced in the servicing missions.
worldmags
worldmags
worldmags
Chasing the Moonshadow
July’s
South Pacific Eclipse On July 11th a lot of ocean and a few tiny bits of land will lie under a Moon-blackened Sun.
The third total eclipse of the Sun in three years is coming up on July 11th, when the long, thin finger of the Moon’s shadow will again draw its tip across Earth’s surface. But unlike the 2007 and 2008 total eclipses, which offered many possibilities for land-based viewing, the 11,000-kilometer (6,800-mile) path of the 2010 eclipse is confined almost exclusively to the South Pacific Ocean.
The Path of Totality Total eclipse begins at sunrise almost 2,000 km northeast of New Zealand, at 18:15 Universal Time. Five minutes later the Moon’s shadow makes the first of its very few appearances on terra firma. The island of Mangaia is a mountainous volcanic remnant in the Cook Islands just south of the eclipse path’s central line. The duration of totality here is 3 minutes 18 seconds, with the Sun 14° above the horizon. The northern edge of the shadow’s umbra (totaleclipse zone) just misses Tahiti in French Polynesia, passing a tantalizingly close 20 kilometers south of the island.
fred espenak and jay anderson
Just to the east, several atolls of the Tuamotu Archipelago are more fortunate. Tiny Haraiki and Tauere are deep in the eclipse path, but neither has facilities of any kind. The slightly larger Hikueru atoll does have a territorial airport in support of its small permanent population. Totality here lasts 4 minutes 35 seconds. When greatest eclipse occurs, at 19:33:31 UT, the duration on the central line is 5 minutes 20 seconds — but this point is hundreds of kilometers from any land. Nearly 40 minutes later and 1,000 kilometers farther southeast, totality crosses Easter Island, one of the world’s most remote inhabited locations. The landscape is dominated by three extinct volcanoes and 887 mysterious stone statues carved a thousand years ago by the thriving inhabitants at the time. From the capital, Hanga Roa, the Sun’s altitude is 40° during the 4 minutes and 41 seconds of total eclipse. Tourism is Easter Island’s main industry, and the eclipse will bring record numbers to this remote destination. The shadow then must travel 3,700 kilometers to reach its final landfall in extreme southern South America. ALL ECLIPSE PHOTOGRAPHS © FRED ESPENAK
32 worldmags
January 2010
sky & telescope
worldmags
19:3
0
00 20:
30
20:
00 21:
a
s
d en
t se un s t
% 60
t un sun se se t t
s egin
T
eb
ips Ecl
e
m u im
19:00
UT 18:30
ise unr at s
e
ax M
LI
d se
TA
lip ec
TO
% 40
Greatest eclipse duration
% 20
OF
ps e
n
ris sun
ec li
% 80
t se a clip
art ial
%
en pse
fp
60
Ecli
mit o
% 80
The eclipse fortunately occurs during the “dry” season, though this is a relative term at best for tropical and subthou tropical locations. Satellite cloud-cover data show that the sunniest spots lie at the lowest latitudes, favoring French Polynesia and the Tuamotu Archipelago. Mangaia lies within the subtropical high-pressure belt circling the globe at 30° south latitude, but it has the misfortune to be close to the South Pacific Convergence Zone (SPCZ). Winds from the eastern and western Pacific converge in the SPCZ, producing a band of enhanced cloudiness and showers that meanders in response to local conditions. This gives Mangaia an average cloudiness of 63% and many rainy days. Tahiti’s clear-sky prospects are better. Average cloudiness at Papeete’s airport for the past 20 years is a promising 48%. Sunshine for July averages 68% of the maximum possible (that is, 68% of daytime is sunlit). The surrounding waters are less cloudy, so prospects on the central line south of the island will be even better. The
P AT H
rn l i
Y
Weather Prospects Wea
Northe
Su
Chil mountainous region has no suitable viewing sites, Chile’s tourist resort of El Calafate offers promise but Argentina’s A the final opportunity before the shadow’s umbra lifts as th from Earth at sunset and returns to space.
ds at sunrise
OCEAN ECLIPSE The July 11th total eclipse begins at sunrise northeast of New Zealand, sweeps across the South Pacific for 2½ hours, and ends at sunset over a wild region of South America. Only 0.48% of Earth’s surface experiences totality, but a much larger area sees a partial eclipse. At any location, interpolate between the red lines to find the percent of the Sun’s diameter that the Moon will cover at maximum partial eclipse. The blue time lines show when this will happen, in Universal Time (GMT).
a e ps i s l ec at E ins m g e u eb xim Ma Eclips e ps cli
: CA S &T
SE Y
RE
ED
added advantage of mobility that a ship provides makes cruise ships off Tahiti the venue of choice for this eclipse. East of Tahiti, satellite observations show that average cloudiness is 5% less than at Papeete. At Hao, near the southern edge of the path, land-based observations show the average cloudiness to be just over 50%, and satellite observations are even more favorable. Easter Island’s more southerly latitude dims its weather prospects. The island is often enveloped in frontal systems
▴ Just
before totality during the eclipse of March 29, 2006, author Fred Espenak took this rapid series of images capturing the crescent Sun’s breakup into Baily’s beads on the Moon’s edge.
◀ Partial
and total phases of the 2006 eclipse.
▶ Fred
and Nan Espenak take a break from their cameras to watch totality from Jalu, Libya, in 2006.
worldmags
Sk yandTelescope.com
January 2010
33
worldmags
FRED ESPENAK
FOR MORE INFORMATION The NASA Solar Eclipse Bulletin for 2010 contains detailed local predictions, tables, maps, and weather prospects. For a free copy of the 77-page book, email the author at
[email protected]. It is available in PDF format at eclipse.gsfc .nasa.gov/SEpubs/2010/rp.html. More information, updates, maps, and diagrams are at eclipse.gsfc.nasa.gov/ SEmono/TSE2010/TSE2010.html.
sweeping up from the Southern Hemisphere’s “Roaring Forties” latitudes. Average cloud cover is 69%, and the percent of possible sunshine is just 50%. The island’s volcanoes are important cloud-makers on their leeward sides, so observers are advised to select coastal sites exposed to the onshore wind. Cloudiness changes constantly from one location to another. In the South American mountains, cloud-cover prospects in the El Calafate region are reasonable with an average value of 54%. However, the low altitude of the Sun makes this a challenging venue, as any amount of cloud will appear thicker near the horizon. Low clouds are frequent during this season, probably generated in large part by the local lakes. Finding a site upwind from the lakes may make the difference in successfully viewing the total eclipse suspended just above the distant Andes peaks. While the 2010 eclipse offers challenges to prospective eclipse viewers, it
S&T: GREGG DINDERMAN
Chasing the Moonshadow
E A S TE R I S L AND TO U R For eclipse chasers seeking a land-based site, Sky & Telescope is cosponsoring a cruise to Easter Island. See SkyandTelescope.com/ easterisland.
will be the last opportunity to observe the Sun’s corona for more than two years. The next total eclipse occurs November 13–14, 2012 — visible at sunrise from northern Australia but mostly, again, from the South Pacific. ✦ Astronomer Fred Espenak (NASA/Goddard Space Flight Center) runs the websites eclipse.gsfc.nasa.gov and www.MrEclipse .com, and he coauthored the recently published Totality: Eclipses of the Sun (3rd edition) with Mark Littmann and Ken Willcox. Meteorologist Jay Anderson (University of Manitoba) has made eclipse weather forecasts since 1979 and has journeyed worldwide to confirm his predictions in person.
FREE SHIPPING!
ON ALL CELESTRON TELESCOPES AT HIGH POINT SCIENTIFIC
at: Visit us online
intsc www.highpo
ientific.com
Celestron Computerized Mounts PRIORITY DELIVERY FREE SHIPPING
Celestron EdgeHD PRIORITY DELIVERY FREE SHIPPING
CGE Pro – $4,999
CGEM 800 HD – $2,399 CGEM 925 HD – $3,099 CGEM 1100 HD –$3,499 CGE Pro 925 HD– $6,299 CGE Pro 1100 HD – $7,399 CGE Pro 1400 HD – $9,999
Call our Celestron experts toll free at
1(800) 266-9590
or visit our showroom at 442 Route 206, Montague, New Jersey 07827
worldmags
CGEM – $1,399
CG5 – $575
Celestron NexStar SE PRIORITY DELIVERY FREE SHIPPING 4” SE – $499 5” SE –$699 6” SE – $799
8” SE –$1,199 BEST VALUE!
worldmags
IT DOES ALL THE WORK. YOU HAVE ALL THE FUN. The LS-6 with LightSwitch™ Technology combines the most sophisticated optics, mechanics and electronics to bring you the most sophisticated, easiest to use telescope available. Only from Meade®. Aligning a telescope, even a computerized one, is a daunting task. But the LS-6 changes all of that. Just flip the switch and all of the work is done for you in just minutes. Leaving the rest of the evening for you to have all of the fun. Not only is the LS-6 the easiest telescope to use, but with its array of features, it’s one of the highest performance scopes you can buy.
UNPARALLELED MEADE OPTICS Take your pick: Meade’s SchmidtCassegrain (SC) optics for high performance at the best possible price. Or, for the truly discerning who will not tolerate anything but the very best, there is Meade’s Advanced ComaFree™ (ACF™) optical system for the sharpest, brightest image you can get.
HEAVY-DUTY MECHANICAL DESIGN With 4.87" solid aluminum, helically-cut gears and brass worm drives, the motion on the LS-6 is smooth and solid. That, and an oversize aluminum fork arm, guarantees the precision needed for incredibly accurate pointing and tracking.
STATE-OF-THE-ART ELECTRONICS With a 400Mhz BlackFin® processor at its core the LS-6 has enough computing power and speed to take you to the edge of the Universe and back, again and again. It’s the most technologically advanced computer system ever put in a commercial telescope.
MEADE’S EXCLUSIVE ASTRONOMER INSIDE Take a multi-media guided tour of the universe or select your favorite object and the LS-6’s Astronomer Inside™ gives you over four hours of fun and informative audio descriptions of the objects you are viewing in the eyepiece.
OPTIONAL VIDEO MONITOR Experience the whole dazzling multi-media presentation that is built into the LS-6. The video monitor shows you videos, animations and photos of the objects you are viewing. It also provides easy to navigate menus to make using the LS-6 even easier. For more information on the revolutionary LS-6 — or on any of the full line of Meade astronomical products — go to www.meade.com.
NEW! OPTIONAL VIDEO MONITOR AND BRACKET. Designed specifically for the LS-6, this optional 3.5" monitor completes the multimedia experience. Only $99!
6" LS-6 SC - $1,399 • 6" LS-6 ACF - $1,499 ©2010 Meade Instruments Corp. All rights reserved. Specifications subject to change. BlackFin is a registered trademark of Analog Devices. 30-09060.
worldmags
Telescopes.com 800.303.5873
Woodland Hills 888.427.8766
OPT Telescopes 800.483.6287
Astronomics 800.422.7876
Optics Planet 800.504.5897
Scope City Canada • Khan Scopes 800.235.3344 800.580.7160
worldmags
Innovative Astronomy Gear
Hot New Products Our 12th annual roundup of Hot Products highlights the most intriguing new astronomy gear in the worldwide market.
By the Editors of SKY & TELESCOPE
2010 2010 for
What a year! After more than a decade scouring the astronomical marketplace for our annual Hot Products roundups, we have a pretty good idea of what a typical year serves up, and 2010 is anything but typical. Our initial search revealed dozens and dozens of new products. The winnowing process, honed by years of experience, still produced a “short list” with more than twice the usual number of candidates, making our fi nal selection especially difficult. But just because something is new doesn’t mean we consider it “hot.” For that, we need to see an item offering a new technology, providing a simple solution to an old problem, or delivering a remarkable price-to-performance ratio. And that last qualification played a major role this year. Consider, for example, a 120-mm apo refractor that delivers visual performance on par with premium-priced instruments but costs only $1,495 (page 39), or a 10-inch Ritchey-Chrétien astrograph costing about one-fourth what similar instruments did just a couple of years ago (page 42). Whether or not you agree with our picks, we hope you’ll enjoy reading about the products that intrigued us the most.
JUST FLIP THE SWITCH Meade’s LightSwitch technology adds a new level of automation to the set up and use of Go To telescopes. Available with the company’s 6-inch Schmidt-Cassegrain and Advanced Coma-Free telescopes, LightSwitch uses GPS satellites, internal level and magnetic-north sensors, and a built-in medium-field CCD camera (for identifying alignment stars) to automatically initialize the Go To computer. All you do is set the scope down, plug it in, and flip one switch. After a few minutes you’ll be ready to view thousands of celestial objects at the push of a button. And that’s just the beginning — the scope’s integrated multimedia material is as educational as it is entertaining. Watch for our review in the coming months.
36 worldmags
January 2010
sky & telescope
Meade 6-inch LightSwitch telescopes US price: from $1,299 Meade www.meade.com
S &T: D
EN N I
S DI
C I CC
O
worldmags
S&T: DENNIS DI CICCO
THERE’S AN APP FOR THAT HAT
US price: from $11.99 Available from the iPhone App Store http://star-map.fr
AstroTrac Travel System ▶ US price: about $2,500 AstroTrac www.astrotrac.com
S& D T: EN N IS
RO
N
Edge HD Telescopes US price: from $1,299 Celestron www.celestron.com
STELLAR PERFORMANCE Billed as aplanatic Schmidt telescopes, the Ed EdgeHD HD series i represents t th the firstt major j redesign of the Schmidt-Cassegrain optical system that Celestron introduced in the 1960s. The addition of a two-element field flattener and coma corrector in the scope’s main baffle tube produces pinpoint star images across the whole field of today’s large-format CCD cameras. And a new mirror-support system reduces the image shift that was often the bane of earlier Schmidt-Cassegrain telescopes. Watch for our review in the coming months.
CO
ST
IC
LE
IC
IT’S IN THE BAG CE
D
worldmags
Starmap
Want to know what that bright star is in the morning twilight? Now you can find out with an app for your Apple iPhone or iPod Touch. Starmap is a full-featured planetarium program with top-notch graphics, which can show you where the Sun, Moon, planets, up to 2½ million stars, and thousands of deep-sky objects are located in your sky. Input your location and time manually, or let the GPS feature of your iPhone do it automatically. Starmap is available in English, Spanish, French, German, Italian, Japanese, Dutch, and Danish. sh.
It doesn’t get much more portable than this — the entire equatorial tracking setup pictured here (sans telescope) fits in a shoulder bag just 6 inches (150 mm) in diameter and 29½ inches long. Weighing about 26 pounds (12 kg), the Travel System from AstroTrac has a payload capacity of 33 pounds, making it ideal for cameras and small telescopes. Its tracking accuracy is sufficient for unguided exposures several minutes long, depending on your camera’s focal length. The heart of the Travel System is the TT320X tracking mount, an updated version of the model we reviewed in the October 2008 issue, page 38. Sk yandTelescope.com
January 2010
37
worldmags
Innovative Astronomy Gear
Nautilus Motorized Filter Wheels
AFFORDABLE FILTER WHEEL P i d more like Priced lik manually ll operated t d models, d l th the Orion Nautilus Motorized Filter Wheel is an excellent value for those looking to add computer automation to their imaging systems. Versions are available that hold four 2-inch or seven 1¼-inch filters. Both require less than 1 inch of back focus, are powered by USB computer connections, and are compatible with 64-bit Vista, Windows 7, and ASCOM. T-threads on both sides of the body and an included 2-inch nosepiece provide a variety of mounting options.
FirstScope
Digital Display Gauge ▾
US price: $49.95 Celestron www.celestron.com
Available on select William Optics telescopes William Optics www.williamoptics.com
ORION TELESCOPES & BINOCULARS
US price: from $429.95 Orion Telescopes & Binoculars www.oriontelescopes.com
STARTING OUT RIGHT
S&T: DENNIS DI CICCO
Don’t let the toy-store price fool you; the exceptionally well-designed Celestron FirstScope received praise from the S&T staff, as well as high marks in our Quick Look review in the October 2009 issue, page 40. The intuitively easy-to-use 3-inch reflector features a solid Dobsonian-style mount and quality construction throughout. The rack-and-pinion focuser accepts standard 1¼-inch eyepieces and is supplied with 20- and 4-mm eyepieces that yield 15× and 75×, respectively. It’s one the best values we’ve ever seen for a “beginner’s” telescope.
S&T: DENNIS DI CICCO
Red Dot Finder Heater US price: $25 Kendrick Astro Instruments www.kendrickastro.com
PRECISSION FOCUSING
KENDRICK ASTRO INSTRUMENTS
DEW BE GONE
38 worldmags
January 2010
sky & telescope
Red dot fi Red-dot finders nders are universally praised for their simplicity and intuitive operation. But their viewing windows are often the first things to dew up under a clear sky. Now Kendrick Astro Instruments, long known for its dew-fighting innovations, has a custom-made window heater for one of the most popular styles of red-dot finder. The 12-volt DC heater draws just 0.2 amp. It’s an elegant solution to a common problem.
The Crayford-style Crayford style focuser on select William Optics telescopes now includes a built-in digital readout accurate to one-hundredth of a millimeter. The fully electronic system reads the focuser’s position from a special encoder strip located beneath the engraved scale on the drawtube. The gauge makes it a snap to zero in on the precise focus for digital cameras.
worldmags
DELIGHTFUL SKYWATCHER
S&
S&T: DENNIS DI CICCO
The price may not look like it belongs to a 120-mm (4¾-inch) apo refractor, but the views through the eyepiece certainly do. Reviewed in the October 2009 issue, page 38, the SkyWatcher SW 120mmED Refractor offers color-free, crisp, contrasty views that are on par with apo refractors costing thousands of dollars more. Making the deal even sweeter, the f/7.5 refractor (shown on an optional mount) comes with a 2-inch diagonal, 20- and 5-mm eyepieces, a 9 × 50 finder, tube rings, a Vixen-style dovetail mounting bar, and a carrying case.
T: D EN N IS DI CIC CO
100° Eyepieces
EXPANSIVE VIEW
US price: from $399 www.televue.com www.explorescientific.com www.tmboptical.com
For or the third year in a row row, eyepie eyepieces with an incredible 100° apparent field of view have been selected as Hot Products. It’s understandable, since observers worldwide have raved about the experience of looking into an eyepiece where you have to roll your eye around to take in the whole scene. In addition to two new Ethos eyepieces (10- and 21-mm) from Tele Vue, the company that pioneered the 100° astronomical eyepiece, there are two models from TMB Optical (9- and 16-mm) and three from industry newcomer Explore Scientific (9-, 14-, and 20-mm). Check out the respective company websites for complete details and prices.
SW 120ED Refractor US price: $1,495 Sky-Watcher U.S.A. www.skywatcherusa.com
Hyperion Astrograph
DEEP-SKY HEAVYWEIGHT
US price: $10,000 Starizona www.starizona.com
Several everal years in development development, the Hyperion 12½ 12½-inch f/8 astrograph is designed for large-format astrophotography. The Harmer-Wynne optical system promises flatfield, diffraction-limited performance across a 70-mm-diameter (1.6°) image circle with less than 10% vignetting. A host of advanced features such as carbon-fiber tube, temperature-compensated focusing, and built-in instrument rotator included in the base price make this a serious entry in the rarified world of premium astrographs.
worldmags
S&T: DENNIS DI CICCO
Sk yandTelescope.com
January 2010
39
worldmags
Innovative Astronomy Gear
A FLATTER FIELD
S&T: SEAN WALKER
With only a few noteworthy (and (a expensive) exceptions, refractors need optional field flatteners in order to deliver acceptable star images across the field of today’s DSLR cameras. Custom-designed flatteners usually cost hundreds of dollars, but the Astro-Tech 2″ Field Flattener is only $150. Furthermore, it’s designed for any refractor with a focal ratio between f/6 and f/8. And there are reports that it helps flatten the field of Astro-Tech’s Ritchey-Chrétien astrographs (see page 42). The flattener was reviewed in the September 2009 issue, page 38.
2-inch Field Flattener US price: $150 Astronomy Technologies www.astronomytechnologies.com
TMB92 Light US price: $1,495 TMB Optical www.tmboptical.com
S&
T: D
EN
N IS
DI
CIC
CO
LIGHT APO StarBlast 6i IntelliScope
TMB-92 The TMB 92 Signature Series Refractor got such a rave review in our March 2009 issue, page 36, that we could not help but take note when the company introduced a new “light” version costing hundreds of dollar less. Featuring the same 92-mm f/5.5 triplet objective as the original, the light version has a smaller-diameter tube and the premium Feather Touch focuser has been replaced with a conventional dual-speed 2-inch focuser. Same great views; new lower price.
US price: $399.95 Orion Telescopes & Binoculars www.oriontelescopes.com
NO MORE PINCHED FINGERS
SMARTER STARBLAST The 6-inch 6 i h f/5 Newtonian N t i refl flector t that received an excellent review in our September 2008 issue, just got a brain. Orion’s StarBlast 6i IntelliScope now includes the company’s time-tested computerized object locator, which makes it a breeze to find more than 14,000 celestial objects stored in its built-in database. The feature-packed scope comes on a fully assembled Dobsonian-style mount that we found to be exceptionally beginner friendly without compromising the needs of experienced observers. 40 worldmags
January 2010
sky & telescope
FARPOINT ASTRONOMICAL RESEARCH
ORION TELESCOPES & BINOCULARS
Eukleídes Binocular Mount US price: $485 Farpoint Astronomical Research www.farpointastro.com
By “literally turning it inside out,” the folks at Farpoint Astronomical Research have made the traditional parallelogram binocular mount stiffer, more resistant to vibration, and safer (no accessible moving parts to pinch fingers). An internal sliding counterweight adds to the mount’s elegant appearance. There are a variety of options available for attaching binoculars to the unit.
worldmags
Pressure-tuned Solar Filter Lunt Solar Systems www.luntsolarsystems.com
QUANTUN SCIENTIFIC IMAGING
COMPACT CCD CAMERA
QSI 583 CCD Camera US price: from $3,595 Quantum Scientific Imaging www.qsimaging.com
No CCD sensor in recent memory has generated as much excitement as the 8.3megapixel Kodak KAF-8300 with tiny 5.4-micron pixels. All the major manufacturers of astronomical CCD cameras offer models with this detector, but those from Quantum Scientific Imaging caught our eye, because the built-in filter wheel is so close to the sensor that it works with standard 1¼inch filters. This can save hundreds of dollars compared to cameras that use external filter wheels and, by necessity, larger filters.
DREAM CELLULAR
CAST MIRROR BLANKS
worldmags
TUNING IN THE SUN
LU
NT
SO
R LA
SY
ST
EM
S
Even ven though the Sun has been notably absent of spots lately, it’s still a fascinating target for telescopes equipped for viewing in hydrogen-alpha (H-alpha, for short) light. Long a leader in the field of H-alpha filters, Lunt Solar Systems has developed a new pressure-tuning method for rapidly shifting the passband of its etalon-based fi lters by more than 0.75 angstrom. A quick turn of the pressure regulator allows you to see the changing appearance of solar features that are Doppler shifted by their motion toward and away from us. The system is seen here installed on the company’s LS60THa/B1200CPT solar telescope priced at $1,493.
Ligh Lightweight mirrors have been the Holy Grail of telescope makes (both amateur and professional) for decades. Reducing a mirror’s mass reduces ama the time it takes to adjust to temperature changes. It also reduces the mass and complexity of the optical support system and the telescope in general. A new start-up company, Dream Cellular, is using sophisticated computer technology to design and cast some of the most advanced lightweight mirror blanks ever made for telescopes. Having as Cellular Mirrors little as 25% of the mass of a conventional solid mirror, the blanks still exceed the stiffness of a Dream Cellular www.dreamcellularllc.com monolithic disk.
TRIO OF TITLES It’s no surprise that we like books books, but three titles captured our fancy this year. Part coffee-table book and part observer’s guide, the lavishly illustrated Atlas of the Messier Objects ($54.95, Cambridge University Press) breathes new life into the sky’s most popular deep-sky objects and the people who discovered them. The Cambridge Double Star Atlas ($35, Cambridge University Press) is a pure observer’s guide, with data and charts for hundreds of multiple stars covering the entire sky. The new edition of Star Testing Astronomical Telescopes ($34.95, Willmann-Bell) is a major update of a work that should be on the shelf of every observer who wants to get the most from his or her telescope. We highly recommend all three titles.
Three Books Cambridge University Press www.cambridge.org Willmann-Bell www.willbell.com
Sk yandTelescope.com
January 2010
41
worldmags
Innovative Astronomy Gear
LEAVE THE COMPUTER HOME Many deep deep-sky sky astrophotographers shooting with DSLR cameras don’t want to lug a computer outside to run an autoguider. Fortunately, there’s now the StarShoot Solitaire AutoGuider from Orion Telescopes & Binoculars. The stand-alone unit has a 3.8-ounce guider head with a CMOS sensor that fits in conventional 1¼-inch focusers and a palm-size control box that runs on 12-volt DC power. The Solitaire is compatible with any mount that complies with the de facto SBIG ST-4 autoguiding standard.
StarShoot Solitaire AutoGuider US price: $599.95 Orion Telescopes & Binoculars www.oriontelescopes.com ORION TELESCOPES & BINOCULARS
8- and 10-inch Ritchey-Chrétien Astrographs
CASSEGRAIN COLLIMATION For many years Newtonian telescope owners have enjoyed the benefits of laser collimators to align the optics of their scopes during daylight. Now HoTech Corp. has expanded its line of laser collimation tools to include a unique system for Cassegrain telescopes. The Advanced CT Laser Collimator uses a target with three built-in lasers and a special reflector that fits in the scope’s eyepiece holder, providing a highly accurate double-pass optical arrangement.
Advanced CT Laser Collimator US price: about $500 HoTech Corp. www.hotechusa.com
SWEET ASTROGRAPHS
HOTECH
S&
T: D
EN
NI
S
DI
CI
CC
O
US price: $1,395 (8-inch), $2,795 (10-inch) Astronomy Technologies www.astronomytechnologies.com
Ritchey-Chrétien refl regarded among today’s elite Ritchey Chrétien reflectors flectors are highly reg astrophotographers, and premium instruments often carry price tags starting at about $1,000 per inch of aperture. So it’s the best kind of “sticker shock” to see the prices for Astro-Tech’s 8- and 10-inch f/8 Ritchey-Chrétiens, which pack features too numerous to list here. Our review of the 8-inch scope appears in last month’s issue, page 38, and our initial hands-on look at the 10-inch suggests that it will be equally exciting for deep-sky astrophotographers.
SG-4 Autoguider
Twenty Group forever changed the world of deep-sky wenty years ago the folks at Santa Barbara Instrument Instrum astrophotography with their introduction of its now-legendary ST-4 autoguider. The latest model in the company’s evolution of stand-alone autoguiders is the SG-4. You only need a separate computer for a one-time calibration with your telescope mount. After that, the SG-4 runs independently, making it ideal for DSLR photographers who want to keep things simple in the field. Indeed, the SG-4 is billed as a “smart” autoguider that features one-button operation. 42 worldmags
January 2010
sky & telescope
SBIG (2)
ONE-BUTTON AUTOGUIDING
US price: $995 Santa Barbara Instrument Group (SBIG) www.sbig.com
worldmags
A PAIR OF PORTABLE GEMS Rated for payloads l d off 40 and d 90 pounds, d respectively, i l Celestron’s C l ’ CGEM (left) and CGE Pro German equatorial mounts offer unquestionable value when it comes to Go To performance for astrophotographers and observers. Designed for portable operation using 12-volt DC power, both mounts have many advanced features, including precise polar-alignment routines that don’t require clear views of the celestial pole. Our review of the heavyweight CGE Pro appears in the November 2009 issue, page 50. S&T:
N RO ST
US price: $1,399 (CGEM) and $4,999 (CGE Pro) Celestron www.celestron.com
DI C ICCO
LE
NIS
CE
D EN
German Equatorial Mounts
LARGE-FORMAT AND SELF GUIDING
worldmags
IG )
Self-guiding STX CCD Camera
SB
After development, SBIG has introduced fter several years of development d its STX line of CCD cameras. Designed to handle largeformat sensors, including Kodak’s 16-megapixel KAF-16803 803 chip, the STX series is unique in featuring the company’s ’s patented self-guiding technology. A separate CCD, mounted nted next to the imaging sensor, monitors guide stars at the edge of the field. New to the STX line is its ability to let users indepennde dently tweak the focus of the guiding chip, which is important mportant given its significant off-axis position due to thee large ima imaging aging ch chip.
US price: $11,875 Santa Barbara Instrument Group (SBIG) www.sbig.com
Versa 108 ED Refractor US price: $1,699 iOptron www.ioptron.com
APO WITH A FIELD FLATTENER
IOP
TRO
N
We were w impressed when the cost of some 4-inch 4 inch apo refractors dropped to the $2,000 range, so there’s little surprise we like the dropp 108-mm (4¼-inch) f/6.1 apo from iOptron. The ED-glass Versa 10 objective is fitted to a well-crafted, 114-mm-diameter doublet o assembly with a rotating, dual-speed 2-inch focuser. And tube assem photographers shooting day or night will like the included 2-inch photo field flattener that turns the scope into an excellent “telephoto” lens of 660 mm focal length.
Sk yandTelescope.com
January 2010
43
worldmags
Fred Schaaf Northern Hemisphere’s Sky
New Sights for the New Year A familiar constellation can offer surprises.
“There is nothing new under the Sun,” says one of the most famous expressions of world-weariness. But if you’re an astronomer, you can reply that there’s plenty new beyond the Sun — not to mention, in, on, and around it. And “new” means not just an ever-changing series of events. It also means discoveries of never-beforeknown objects and phenomena — even new kinds of objects and phenomena — in our universe. So astronomy is an opening for newness in our lives. What new sights and perspectives can we look for in the skies of evening at the beginning of this new year? Let’s look high in the east at the time of our all-sky chart, where the constellation Auriga is following Perseus to the zenith for viewers at mid-northern latitudes.
Capella
Stock 10
M38 M36
AKIRA FUJII
M M37
Leaping Minnow
β Tauri
44 January 2010 sky & telescope worldmags
Auriga’s bright open clusters. All beginners quickly learn Capella, Auriga’s zero-magnitude star, and the other stars of the pentagon that constitutes Auriga’s main pattern. Telescope users also soon learn about the three open star clusters in this constellation that were cataloged by French comet hunter Charles Messier: splendid M36, M37, and M38. But how many people know that many of Auriga’s other clusters are visible in small telescopes and binoculars? All but one of these bright clusters are shown in Sky & Telescope’s Pocket Sky Atlas and Sky Atlas 2000.0, which can be purchased at ShopatSky.com. And the remaining cluster — the sparse but fascinating Stock 10 — is labeled in the photograph at left. While you’re studying Epsilon Aurigae undergoing its long, mysterious eclipse for the first time in 27 years (S&T: May 2009, page 58), scan a few degrees west to behold NGC 1664. Sue French discusses NGC 1893, another prominent cluster, on page 65. Lovely little NGC 1907 is a close neighbor to M38. And in easternmost Auriga, solitary NGC 2281 is brighter than — though not as prominent as — the Messier clusters. The Minnow. If you’ve looked inside the Auriga pentagon with your naked eye under a dark sky, have you ever wondered about that strange elongated glow — no, maybe a short line of faint points of light? Though the glow is only a few degrees from M36 and M38, it’s not from those clusters. It’s an asterism that Sky & Telescope senior editor Alan M. MacRobert calls the Leaping Minnow: a Delphinus-like pattern of 5th- and 6th-magnitude stars that’s striking in binoculars — and shown well in the photograph at left. As Sue French points out on page 65, the Minnow is part of the larger asterism Melotte 31. Coming soon. Still hungering for new sights and perspectives? Next month in this column, I’ll tell how Capella was once the brightest star in Earth’s sky, how it shone 46° farther south, and how it used to be not just Earth’s North Star but something more amazing: part of the ultimate double North Star with an even brighter (negative-magnitude) luminary. ✦ Fred Schaaf welcomes your comments at
[email protected].
worldmags
worldmags Advertisement
Master the Science behind the Complexities of Your World Explore the fundamental concepts, tools, and applications of complexity science in this fascinating 12-lecture course taught by an award-winning professor.
R
In fact, complexity science is a discipline that may well hold the key to unlocking the secrets of some of the most important forces on Earth. But it’s also a science that remains largely unknown, even among well-educated people. Now you can discover and grasp the fundamentals and applications of this amazing field with Understanding Complexity. Professor Scott E. Page—one of the field’s most highly regarded teachers, researchers, and real-world practitioners—introduces you to this vibrant and still evolving discipline. In 12 intriguing lectures, you learn how complexity science helps us understand the nature and behavior of financial markets, corporations, native cultures, governments, and other complex systems. Professor Page shows you how ideas and tools such as the tipping point, emergence, the wisdom of crowds, and agent-based computer modeling can effectively take on problems that decision-making theory cannot. Designed to be comprehensive and accessible, the course features a wealth of two- and three-dimensional computer graphics and highly illustrative thought experiments—to say nothing of Professor Page’s outstanding teaching skills, which have earned him numerous accolades.
© Shutterstock.com
ecent years have seen the emergence of the new and exciting field of complexity science—one that has captivated economists, sociologists, engineers, businesspeople, and others. Complexity science can shed light on why businesses succeed and fail, how epidemics spread and can be stopped, and what causes ecological systems to rebalance themselves after a disaster. in complex times, and there is little or no sign of the complexity abating.” While the systems you explore will continue to remain complex, the science behind them will attain a startling new level of clarity. About Your Professor Dr. Scott E. Page is Collegiate Professor of Political Science, Complex Systems, and Economics at the University of Michigan. He received his Ph.D. in Managerial Economics and Decision Sciences from Northwestern University. An external faculty member of the Santa Fe Institute, Professor Page is the coauthor of Complex Adaptive Systems: An Introduction to Computational Models of Social Life. About The Teaching Company We review hundreds of top-rated professors from America’s best colleges and universities each year. From this extraordinary group, we choose only those rated highest by panels of our customers. Fewer than 10% of these world-class scholarteachers are selected to make The Great Courses®.
We’ve been doing this since 1990, producing more than 3,000 hours of material in modern and ancient history, philosophy, literature, fine arts, the sciences, and mathematics for intelligent, engaged, adult lifelong learners. If a course is ever less than completely satisfying, you may exchange it for another or we will refund your money promptly. Lecture Titles 1. Complexity—What Is It? Why Does It Matter? 2. Simple, Rugged, and Dancing Landscapes 3. The Interesting In-Between 4. Why Different Is More 5. Explore Exploit— The Fundamental Trade-Off 6. Emergence I— Why More Is Different 7. Emergence II— Network Structure and Function 8. Agent-Based Modeling— The New Tool 9. Feedbacks—Beehives, QWERTY, the Big Sort 10. The Sand Pile— Self-Organized Criticality 11. Complexity versus Uncertainty 12. Harnessing Complexity
SAVE $160! O F F ER G O O D U N TIL J AN U ARY 2 9 , 2 0 1 0
By the conclusion of Understanding Complexity, you’ll have a new lens through which to view and make sense of your increasingly complex world. “Like it or not,” says Professor Page at the start of the course, “we live
1-800-TEACH-12 (1-800-832-2412) Fax: 703-378-3819
Special offer is available online at
www.TEACH12.com/4sky Charge my credit card:
The
Great Courses
®
About Our Sale Price Policy Why is the sale price for this course so much lower than its standard price? Every course we make goes on sale at least once a year. Producing large quantities of only the sale courses keeps costs down and allows us to pass the savings on to you. This approach also enables us to fill your order immediately: 99% of all orders placed by 2 pm eastern time ship that same day. Order before January 29, 2010, to receive these savings.
THE TEACHING COMPANY 4151 Lafayette Center Drive, Suite 100 Chantilly, VA 20151-1232 ®
Priority Code 37114
n
n
n
n
Account Number
Exp. Date
Signature
Please send me Understanding Complexity, which consists of twelve 30-minute lectures plus a Course Guidebook.
Name (please print) Mailing Address
n DVD $39.95 (std. price $199.95) SAVE $160! plus $5 shipping, processing, and Lifetime Satisfaction Guarantee
n Check or Money Order Enclosed Special price for shipping, processing, and lifetime satisfaction guarantee—this offer only. *
Non-U.S. Orders: Additional shipping charges apply. For more details, call us or visit the FAQ page on our website.
** Virginia residents please add 5% sales tax.
Advertisement
City/State/ZIP Phone (If we have questions regarding your order—required for international orders)
n FREE CATALOG. Please send me a free copy of your current catalog (no purchase necessary). Special offer is available online at www.TEACH12.com/4sky Offer Good Through: January 29, 2010
worldmags
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] 46 January 2010 worldmags
sky & telescope
worldmags
Sky at a Glance
January 2010
MOON PHASES SUN
MON
TUE
WED
THU
FRI
1
2
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
25
26
27
28
29
30
31
NIGHT: The Quadrantid meteor shower should be somewhat active late on these nights, but strong moonlight will be a severe hindrance.
2
EVENING: Mars rises about 7° left of the Moon. And Earth reaches perihelion, its closest approach to the Sun, for 2010.
7
LAST-QUARTER MOON (5:39 a.m. EST).
8
PREDAWN: Saturn’s rings are tilted 4.9° with respect to Earth, the widest they appear from October 2008 through August 2010.
11
DAWN: Antares is very close to the waning crescent Moon as seen from North America. In easternmost North America, the Moon occults Antares around sunrise; for details see SkyandTelescope.com/jan-11-2010.
13
DAWN: The very thin crescent Moon is 5° or 6° lower right of Mercury very low in the southeast a half hour before sunrise: a difficult but rewarding observation. Bring binoculars.
15
NEW MOON (2:11 a.m. EST). An annular solar eclipse is visible in a thin path from Africa to China, and a partial solar eclipse takes place across much of Asia and Africa and parts of Europe; see SkyandTelescope.com/jan-15-2010.
SAT
3
24
2– 4
PLANET VISIBILITY ◀ SUNSET
MIDNIGHT
SUNRISE ▶
Mercury
Visible January 12 to February 9
Venus
Hidden in the Sun’s glow all month E
Mars Jupiter
SW
SE
S
W
W E
Saturn
S
SW
PLANET VISIBILITY SHOWN FOR LATITUDE 40o NORTH AT MID-MONTH.
16–29 DAWN: Mercury has a good apparition. It’s easiest to see very low in the southeast about 45 minutes before sunrise. 17
EVENING: The thin crescent Moon is about 5° lower right of Jupiter in the west-southwest as twilight fades.
23
FIRST-QUARTER MOON (5:53 a.m. EST).
27
NIGHT: Mars is closest to Earth, appearing bigger through a telescope than at any other time from 2009 through 2013. But Mars appears almost the same size from mid-January through mid-February.
29
NIGHT: Mars is at opposition: rising around sunset and setting around sunrise. And the full Moon, which is also opposite the Sun, hovers near Mars all night.
30
FULL MOON occurs at 1:18 a.m EST (10:18 p.m. PST on the 29th). Just three hours later, the Moon makes its closest approach to Earth for 2010: 221,600 miles or 356,600 km, 7% less than its average distance. This will make the full Moon appear slightly larger than usual.
IMAGE BY NASA / JIM BELL / MIKE WOLFF
An asian eclipse
worldmags
The Hubble Space Telescope was able to capture exquisite detail during Mars’s record-close approach in August 2003. You’ll never see Mars like this through the eyepiece of a telescope, but it’s a goal to dream of.
See SkyandTelescope.com/ataglance for details on each week’s celestial events.
Sk yandTelescope.com
January 2010
47
worldmags
Facing North
Northern Hemisphere Sky Chart
15h Al
Z
co
h
18
E A
Ve
N
G
iza
r
E
H
ga
M
+60°
I
B
r
Thuban
DRACO Z
A
12 h
Di
g Bi er pp
c Fa
G
G
A
in
M
B
URSA MINOR
Little Dipper
U
B
A
A
R
JO
S
+80°
R
A
B
rn he s s
Q
D
g
N
E
D
rt
D
M81
S
M82
U
M LE IN O
PAR
DAL
D
Dou Clus ble ter +60° O
b ne A De
x
E
G
M 42
K
B
ge Ri
s
O2
E
E
I Q
Z
H
S TU CE
l
B
ERID ANUS
M
IS
41
M
D
A
T
B
–20°
R
S FORNAX
a
c Fa
ar
h Ad
JO
E
i
M
B
A
Z
t
T O R E Q U A
A
0h
A
LU
G
le rc Ci
A
N
D
Z
B
riu
N
LE PU
PEGASUS
H M
M Ja
A
CA EL UM
S –40° Q
3h
sky & telescope
G
S E C IS P
X
B
A
A
IAN TR
H
TA UR US
A
B
3 M3
M
B
LU
L
Great Square
1 M3 G
34 M
GU
des
tri
IO
lla
Be
R
Moo Jan 22n E C L I P T I C
Hya
A
O
39
A B G
a
A
C
ANDROMEDA
IS
E
G
B
A
Mir
Si A
C
SE
61
ELO
+20°
IES
B
B
6h
LA
CA
SSI O
I G
O
M50
M47 M46
ng
M52
PEI A R
AR
s
0°
A
G
R CE
D
l
B
Al go
Z
e
L
A
us
lge
te
ran
M
CAM
D
E
Be
A
eba
E
O
+80° A
S
I
H
G
Plei
ade
Ald
TA
G
R SE U
AURIGA
M38 M36
M37
Zenith
G
1 2 3 Star 4 magnitudes
48 January 2010
ZC E P HE US
G
PE
Capella
A
B Q
M35
M
Mo Jan on 26 Z
Procyon
A
S RO CE NO MO
M48
0
A
X
S CANI R MINO A
B
HYDRA
B
M
Y N
A
h
GEMINI
Castor
Pollux
M44
B
CAN CER
G
M67
A
9
Facing East
M Jan oon 29
29 M
Polaris
B
L
A
s
–1
worldmags
G
A
R
ar
N
O
LE O
M
Facing South
C
U
L
P
T
O
R
worldmags
c Fa
in
g
N
W L
Binocular Highlight:
WHEN
Ghostly Galaxy M74
Late November
11 p.m.
Early December
10 p.m.
Late December
9 p.m.
Early January
8 p.m.
Late January
Dusk
These are standard times.
R
B
Y
A
re lbi
o
N Cro
Using the Map
C
G
DELP
HINU
S
C
M2
7
Y
G
HOW
h
US
B
A
Q
RI UA
g
SW
Jupiter
ci Fa
n
worldmags
Example: Rotate the map a little so that “Facing SE” is right-side up. Nearly halfway from there to the map’s center is the constellation Orion. Go out, face southeast, and look halfway up the sky. There’s Orion! 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. Jupiter and Mars are positioned for mid-January.
AQ
Moon n 19
Facing West
M2
E
EQUULEUS
M15
21
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.
Galaxy Double star
You can create a sky chart customized for your location at any time at SkyandTelescope.com/ skychart.
L ast month we looked at the finest galaxy in the Messier catalog, M31 in Andromeda. This month . . . well, let’s just say that M31 is exceptional. The truth is, most galaxies are difficult binocular objects. M74 in Pisces is far more typical of the breed. Found a little more than 1° northeast of Eta (η) Piscium, M74 is positioned midway, and just below, a line connecting Eta with a nearby pairing of 6th- and 7th-magnitude stars. Pinpointing the galaxy’s location is key to finding this low-surface-brightness object. Seeing M74’s 9.4-magnitude glow isn’t easy even under reasonably good skies. With 10×50 binos and averted vision, I can detect the galaxy only about half the time, observing from my semirural backyard. M74 provides yet another lesson in the importance of magnification when it comes to objects at the threshold of visibility. Using my 15×45 image-stabilized binoculars, I can hold the galaxy in view continuously and even begin to appreciate its ghostly dimensions. Does more light-gathering power help? My 15×70s improve the view slightly, but the extra aperture doesn’t make as much difference as going from 10× to 15×. If your skies aren’t dark enough to pull in M74, try for the nearby double star, Psi1 (ψ1) Piscium. This pairing marks the top right of a large, squat Y asterism. Psi1 is an attractive double that features 5.3- and 5.4-magnitude stars separated by a scant 30″. That’s tight for most binoculars, but I can split the duo cleanly in my 10×50s — as long as the binos are mounted. Hand held? Forget it. Here again, boosting the power helps — the extra magnification of my 15×45s make easy work of this gem. ✦ — Gary Seronik
Z1
PISCES
5°
bin
ocular view
M74
Variable star Open cluster Diffuse nebula
H
Globular cluster Planetary nebula
Sk yandTelescope.com
January 2010
49
worldmags
Planetary Almanac
Sun and Planets, January 2010
Mercury
Nov
11
Jan 1
21
Sun
31
Right Ascension
Declination
Elongation
Magnitude
Diameter
Illumination
Distance
h
m
–23° 02′
—
–26.8
32′ 32″
—
0.983
h
m
–17° 31′
—
–26.8
32′ 28″
—
0.985
1
h
19 20.7
m
–20° 30′
9° Ev
+2.9
9.6″
6%
0.703
11
18h 30.2m
–19° 56′
14° Mo
+1.7
9.5″
14%
0.711
21
18h 30.6m
1
18 44.9
31
Venus Mercury 1
20 53.2
31
16
Mars
–21° 06′
24° Mo
–0.1
7.6″
48%
0.888
h
m
–21° 58′
24° Mo
–0.2
6.3″
69%
1.066
1
h
18 33.7
m
–23° 39′
3° Mo
–4.0
9.8″
100%
1.708
11
19h 28.3m
–22° 41′
1° Mo
—
9.7″
100%
1.711
21
20h 21.7m
31 Venus
1
16
31
Jupiter
19 10.9
–20° 35′
2° Ev
–4.0
9.8″
100%
1.710
h
m
–17° 28′
5° Ev
–3.9
9.8″
100%
1.705
1
h
9 29.3
m
+18° 48′
141° Mo
–0.8
12.7″
96%
0.739
16
9h 14.8m
+20° 28′
160° Mo
–1.1
13.8″
99%
0.679
31
8h 51.6m
31 Mars
Jupiter
16
21 13.2
1
Saturn
Saturn Uranus
+22° 19′
175° Ev
–1.3
14.1″
100%
0.665
h
m
–13° 39′
46° Ev
–2.1
35.0″
99%
5.637
h
m
21 55.1
31
22 20.4
–11° 20′
22° Ev
–2.0
33.4″
100%
5.896
1
12h 19.6m
+0° 22′
96° Mo
+0.9
17.8″
100%
9.323
31
12h 19.4m
16
+0° 33′
127° Mo
+0.7
18.7″
100%
8.864
h
m
–3° 18′
58° Ev
+5.9
3.4″
100%
20.603
h
m
23 37.0
Neptune
16
21 49.4
–13° 37′
29° Ev
+8.0
2.2″
100%
30.878
Pluto
16
18h 15.5m
–18° 18′
22° Mo
+14.1
0.1″
100%
32.678
16 The table above gives each object’s right ascension and declination (equinox 2000.0; no longer equinox of date) 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. (One a.u., the mean Earth–Sun distance, is 149,597,871 kilometers, or 92,955,807 international miles.) For other dates, see SkyandTelescope.com/almanac.
Uranus Neptune
Planet disks at left have south up, to match the view in many telescopes. The blue ticks indicate the pole currently tilted toward Earth.
10"
14 h 12h RIGHT ASCENSION
16 h
18h
+40°
Vega
HERCULES
Castor Pollux
LEO
Arcturus
+20° +10° 0° AQUI LA
Jan 29–30
Mars Regulus
Saturn
VIRGO
OPHIUCHUS
6h GEMINI
2h
4h
25
Pleiades
ECL CANCER
4
Betelgeuse
IPT
22h
0h
ARIES
IC
TA U R U S
PEGASUS
22 PISCES
19 E Q U AT O R
LIBRA
Spica
Pluto Antares
–30°
10 am
Sirius
CORVUS
E R I D A NUS
H Y D R A
8 am
4 am
2 am
Midnight
10 pm
+10°
Neptune
–10°
Venus Fomalhaut
6 am
+20°
0°
Jupiter
CETUS
CANIS MAJOR
10
SCORPIUS
SAGITTARIUS
7
+30°
AQUARI US
Uranus
Rigel
–10°
20 h
CYGNUS
Procyon
ORION
Mercury
–40°
8h
10 h
BOÖTES
+30°
DECLINATION
Pluto
8 pm
LOCAL TIME OF TRANSIT 6 pm 4 pm
C APRI C ORN US –30°
2 pm
–40°
The Sun and planets are positioned for mid-January; 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). “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.
50 worldmags
January 2010
sky & telescope
worldmags
worldmags
Saturn’s Moons Jan 16 0h UT
Jan 1 2 3
EAST
WEST
Titan
4 5 6 7 8 9
Tethys
10 11 12 13
Rhea
14 15 16 17
Enceladus
18 19 20 21 22 23 24 25 26 27 28 29
Dione
30 31 The wavy lines represent five Saturnian satellites; the central vertical bands are Saturn and its rings. Each gray or black horizontal band is one day, from 0 h (upper edge of band) to 24h UT (GMT). The ellipses at top show the actual apparent orbits; the satellites are usually a little north or south of the ring extensions.
Sk yandTelescope.com
January 2010
51
worldmags
worldmags
worldmags
Fred Schaaf Sun, Moon, and Planets
Mars at Its Brightest The Red Planet takes center stage. Every evening
in January, Jupiter sets earlier and Mars rises earlier. By month’s end Mars is at opposition: rising around sunset, staying up until dawn, and shining at its closest and brightest for the year. Saturn, much dimmer, rises due east in late evening and is highest in the predawn hours. Finally, as dawn brightens in the second half of January, Mercury climbs into view, putting on a fine show.
E A R LY E V E N I N G Jupiter shines fairly high in the southwest as the sky grows dark on New Year’s Day, but by month’s end it’s much lower and sets soon after the end of twilight (for observers at mid-northern latitudes). For the sharpest views of Jupiter’s globe, point your telescope at it as early in dusk as possible. On January 1st Jupiter blazes in eastern Aquarius at magnitude –2.1, only 2° east of 8th-magnitude Neptune. Jupiter crosses into Capricornus a few
worldmags
Dawn, Jan 10–12 1 hour before sunrise Moon Jan 10
days later, and by month’s end it’s nearly 8° from Neptune. Uranus, at 6th magnitude, remains an easy binocular target just south of the Circlet of Pisces (see our finder chart in last September’s issue, page 55). But Uranus is getting lower. On January 1st it’s more than 40° above the southwestern horizon at twilight’s end, but by January 31st it’s only half that high. Venus remains hidden in the Sun’s glare all month, reaching superior conjunction (passing behind the Sun) on the 11th. It will reappear very low in the sunset in February.
Throughout January and February, Mars appears brighter and bigger (through telescopes) than it has since early 2008 or will again until 2012. Early in January, the cold desert world rises around 7 p.m. and is highest after 2 a.m. Mars reaches opposition to the Sun on January 29th, rising around sunset, climbing highest around midnight, and setting around sunrise. At this relatively distant opposition, campfire-colored and steady-shining Mars
Dawn, Jan 13
Moon Jan 11 10°
Antares
SCORPIUS Mercury Moon
Looking Southeast
Looking Southeast
Castor
About 9 pm Pollux
Moon Jan 1
Moon Jan 2
Mars
Sickle of LEO
EVENING AND NIGHT
30 minutes before sunrise
Moon Jan 12
Jan 1 – 3
G
Regulus Moon Jan 3
Looking East
peaks at magnitude –1.3, a bit dimmer than sapphire-hued, sparkling Sirius. On January 27th Mars makes its closest approach to Earth, at a distance of 0.664 a.u. (61.7 million miles or 99.3 million kilometers). Its apparent diameter then is only 14.1″. (During its record-close approach in August 2003, Mars shone These scenes are drawn for near the middle of North America (latitude 40° north, longitude 90° west); European observers should move each Moon symbol a quarter of the way toward the one for the previous date. In the Far East, move the Moon halfway. For clarity, the Moon is shown three times its actual apparent size. The visibility of objects in bright twilight is exaggerated. The 10° scale is about the width of your fist at arm’s length.
Sk yandTelescope.com
January 2010
53
worldmags
Sun, Moon, and Planets
ORBIT S OF THE PL ANE T S Mars
The curved arrows show each planet’s movement during January. The outer planets don’t change position enough in a month to notice at this scale.
at magnitude –2.9 and appeared 25.1″ across.) For more on observing Mars this season, see page 57 of last month’s issue. As Earth overtakes Mars in their orbital race, Mars appears to retrograde (move westward relative to the stars). This movement carries it 10° in January, from just west of the Sickle of Leo to central Cancer, near Gamma Cancri (Asellus Borealis) and the Beehive Cluster. Saturn rises around 11:30 p.m. on January 1st but two hours earlier by the end of the month. The planet sits almost on the celestial equator, remaining nearly stationary and shining at magnitude +0.8 about 1° north of 4th-magnitude Eta Virginis (Zaniah). Saturn is highest, offering its crispest telescopic image, in the small hours of the morning. Its disk appears to grow slightly this month, from 18″ to 19″. On January 8th the rings achieve a temporary maximum tilt of 4.9° with respect to Earth. After that, the rings start to close back down to a 1.7° minimum tilt in late May.
Earth
Mercury
March equinox
Venus June solstice
Saturn
Uranus Jupiter Neptune Pluto
DAWN Mercury goes through inferior conjunction with the Sun on January 4th and then, over the next few weeks, brightens and climbs into view before sunrise. From January 15th to 30th, observers around 40° north will find Mercury 9° or 10° above
Dusk, Jan 16 –18
Dawn, Jan 30 –31 1 hour before sunrise
Sickle of LEO
Enif
_ Aqr Regulus Jupiter
` Aqr
Moon Jan 31
Mars
Moon Jan 17 Moon Jan 30
b Cap Moon Jan 16
Looking West-Southwest
54 worldmags
January 2010
sky & telescope
Sept. equinox
Sun
1 hour after sunset
Moon Jan 18
December solstice
Looking West
the southeast horizon 30 minutes before sunrise. Look earlier to catch Mercury lower in a darker sky, or later to get a crisper telescopic view.
MOON AND SUN The longest annular eclipse of the Sun until the year 3043 takes place on January 15th, visible in parts of Africa, the Indian Ocean, and China; see SkyandTelescope/ jan-15-2010 for details. The Moon is waning gibbous when it rises about 7° right of Mars on the evening of January 2nd, as shown on page 53. On January 11th the waning lunar crescent occults Antares around sunrise in northeastern North America; for details see SkyandTelescope.com/jan11-2010. Back in the evening sky, the waxing crescent Moon shines about 5° lower right of Jupiter at dusk on January 17th, as shown at left. And the full Moon of January 29th rises, once again, 7° right of Mars. Earth is at perihelion, nearest to the Sun, on January 3rd. It is then 91.4 million miles (147.1 million km) from the Sun, 1.7% less than its average distance. ✦
worldmags
READY TO GO WHEN YOU ARE.
Stellarvue SV160 with Celestron CGE-Pro Mount
Stellarvue SV115T20 Apo with Celestron CGEM Mount
Stellarvue SV115T APO with Celestron CGEM Mount
/KNM[9C[2JQVQD[6QP[*CNNCU
5VGNNCTXWGJCULQKPGFHQTEGUYKVJ%GNGUVTQPVQEQODKPGJKIJGPFTGHTCEVQTQRVKEUYKVJCEQORNGVG NKPGQHRTGEKUKQPEQORWVGTK\GF)GTOCPGSWCVQTKCNOQWPVU6JGUGRCEMCIGUCTGPQYCXCKNCDNG HTQO5VGNNCTXWGQTCP[RTGOKGT5VGNNCTXWGFGCNGT
worldmags
YYYEGNGUVTQPEQO
worldmags
worldmags
INVITES ITS READERS AND FRIENDS TO JOIN FORMER EDITOR IN CHIEF RICK FIENBERG ON A UNIQUE ASTRONOMY VOYAGE
worldmags
Charles A. Wood Exploring the Moon
Craters upon Craters Layered impact features offer visual clues to the Moon’s history. Textbooks often illustrate the concept
example, Theophilus formed close enough to Cyrillus — both are about 100 kilometers (62 miles) across — that the younger crater’s rim sliced through the first, causing debris to flow across the floor of Cyrillus. If the younger crater is larger than the existing one, it eats into it, with varying results. The effects on the younger crater are less obvious, but still visible. Porter and Rutherfurd are two smaller craters on the rim of Clavius. Both impactors hit very uneven terrain; one side of each is high up on the rim of Clavius and the other is on the old crater’s floor. Clavius is nearly 5 km deep, so the younger craters are strongly tilted into the larger, ancient crater and their interiors
of cratering by depicting the impact, excavation, and ejection events on a completely flat terrain. In reality, most lunar impact craters formed on an irregular landscape that already had impact features. Craters typically form on or near pre-existing craters, affecting the appearance of both. To appreciate these effects, let’s examine the textbook case of a crater that impacted onto a maria; Copernicus is a good example. Its outline is nearly circular, and its walls are about equally high on all sides. This symmetry reflects a high-angle impact onto a relatively flat terrain. The effect of a new crater on a pre-existing one depends on their proximity and their diameters. For
The Moon • January 2010 Highlighted Feature
Description
A
Theophilus
Crater (60 miles)
B
Clavius
Crater (140 miles)
C
Steinheil
Crater (40 miles)
D
Nasireddin
Crater (32 miles) N
Phases Last quarter New Moon First quarter Full Moon
31
30 January 7, 10:39 UT January 15, 7:11 UT January 23, 10:53 UT January 30, 6:18 UT
Distances January 1, 21h UT diam. 33′ 36″ January 17, 2h UT diam. 29′ 1″ January 30, 9h UT diam. 33′ 50″
Librations Nicholson (crater) January 1 Cleostratus (crater) January 30 Cusanus (crater) January 31
worldmags
W
E
A
Jan 1
D C S
L ÜK ÍN R KL A N TO N Ü R N Í A N TO N
B
For key dates, black dots on the map indicate what part of the Moon’s limb is tipped the most toward Earth by libration under favorable illumination.
S&T: SEAN WALKER
Perigee 222,900 miles Apogee 252,535 miles Perigee 221,600 miles
Craters that formed over earlier impacts often leave their mark on both features. When Theophilus was excavated, its ejecta covered the floor of older Cyrillus to the Southwest.
Sk yandTelescope.com
January 2010
57
worldmags
worldmags
MICK HYDE
Exploring the Moon
Clavius sports the two smaller craters Porter (upper right) and Rutherfurd (lower right) on its rim; both are slumped inward toward the center of the older, massive basin.
of crater rim elevations found that craters in maria have nearly constant height, whereas craters in the highlands commonly have uneven rims. This reflects the fact that the highlands are typically a billion years older than the maria and the first billion years of lunar history had a much higher cratering rate. During the last 3.5 billion years, nearly every crater formed in the highlands smashed into preexisting craters, affecting both the old and the new. Next time you observe the Moon, see if you can discover more low rims and mounds of debris where craters overlap. ✦ For a daily lunar fix, visit contributing editor Charles Wood’s website: lpod.wikispaces.com.
DAMIAN PEACH
are visibly affected. Both craters have uneven rim heights and their floors are displaced toward the center of the older one. On Clavius’s northern rim, Porter has a very low rim inside of Clavius, and its flat floor is sloped downhill. Rutherfurd, on Clavius’s southern rim, has much more wall-collapse debris under its high rim and its floor and central peak are also offset toward the low side. Steinheil and Watt provide another example of a later crater sloughing off material into a nearby older one. These nearly twin craters are each about 65 km in diameter, though Steinheil cuts the rim of Watt. Its rim is noticeably lower where it overlaps Watt, and most of Watt’s floor is covered by rubbly debris — the missing material from Steinheil’s rim. A final instance of craters interfering with one another is the cluster Orontius, Huggins, Miller, and Nasireddin, which formed in that sequence. Mountains of rock slumped into both Huggins and Miller when Nasireddin formed between them. The effect is most dramatic where masses of slumped rock appear as if they were bulldozed across Miller’s floor. If you look closely, you’ll see that Nasireddin’s rim is somewhat lower on that side. Notice that all of these examples are in the lunar highlands. A study 30 years ago
Near the southeast limb, Steinheil (upper left) and Watt form a prominent pair of similar craters, though the overlapping wall of Steinheil belies its younger age.
worldmags
worldmags
THE ULTIMATE IN ASTRONOMY SHOPPING:
adorama.com
Free Shipping
Same Day Shipping
14 Day Money Back
We Buy
For more details visit our website
Monday thru Thursday & Friday till 1:00PM, on all in-stock items
Please check our website
For more details visit our website
on thousand of items!
MEADE ETX-LS LIGHTSWITCH Ma^k^ohenmbhgZkr>MQ&ELZlmkhghfb\Zem^e^l\hi^_^Z& mnk^lma^fhlmZ]oZg\^]^e^\mkhgb\lZg]himb\l^o^k Ziieb^]mhZ\hglnf^km^e^l\hi^'
Eb`amLpbm\aM^\agheh`r3
'M>E>LL
EQ+))&:
