JANUARY 2008 The Denver

Newsletter of the Denver Astronomical Society One Mile Nearer the

Chilly Sisters About 400 light away and easily seen with the unaided eye, the Pleiades (M45) glitter like blue gems in the dark and signal the coming of winter. Maybe they’re just ice cubes that chill the night. David imaged them from his Chainlube

Image copyright 2007 David Wolf Observatory in Englewood on October 8, 2007. He used a modified Canon Rebel XT and an Orion 80ED at f/6. HAPPY NEW !! JANUARY SKIES can’t keep up with Comet Holmes’ . While you’re looking for Holmes cember 28 it passes left of M31 (the An- Icapriciousness. Just when I thought it check out the cluster M34 to the west of dromeda ), as it drops into the had died, it came back to life. What will , then dip straight south to fine edge- south, and a day later passes the bright it do in January? Only the “Shadow” on spiral galaxy NGC 1023, west of ρ (rho) β (beta) Andromedae. Then, on New knows. Look for it somewhere around Persei. Years Eve it plows through M33, the face- The better-behaved Comet Tuttle will on spiral in , a galaxy that’s so Schedule of Events ...... 2 peak in brightness the first week of the low in surface brightness it’s the hardest Observer month. For a good chart of where it will be Messier object to find despite being the Society Directory ...... 2 look on page 74 of January’s S & T. What largest in sky area. A thought: We ought is interesting about its path across the sky to have a New Years party planned around Michael Carroll, are the objects it will come near. On De- this conjuction, with drinking and danc- ing and so on as an optional activity. January Speaker ...... 3 4 ...... Quadrantid meteor shower peaks BYOB. It’s always fun to sing Auld Lang 8 ...... New moon Astro-Imaging Part 3 ...... 4-6 Syne whilst hoisting a wee dram around 15 ...... First quarter moon the old telescope. 22 ...... Full moon Membership Info ...... back page 29 ...... Last quarter moon Continued on page 7

JanuaryInside The 2008 One Mile Nearer the Stars Page 1 President’s Corner Society Directory President: Wayne Green (303) 530-1023 ooking back can be fun, but look- Email: [email protected] Ling forward always fosters hope Vice President: Keith Pool (303) 718-7273 and excitement. This month we can Email: [email protected] look forward to Comet 8P/Tuttle and Secretary: Darrell Dodge (303) 932-1309 Mars being well placed for evening ob- Email: [email protected] servation. On February 20th we have Treasurer: a lunar eclipse and a special DAS Open Brad Gilman (720) 488-1028 Email: [email protected] House. February will see elections for the Executive Board Members new DAS officers. If you are interested Jack Eastman Ron Pearson Joe Gafford David Shouldice in running for office, contact Dennis Frank Mancini Bryan Wilburn Cochran, Wayne Kaaz or Ivan Geisler Ron Mickle Dan Wray Steve Solon, Past President and toss your hat into the ring. The President Emeritus, Larry Brooks end of March will see the annual DAS Banquet. Committees Van Nattan-Hansen Scholarship Fund We are looking for a new chairman Ron Pearson (Chair) for the Edmund G. Kline Dark Site. P.O. Box 150743 Wayne Green, DAS President Lakewood, Colorado 80215-0743 Candidates should make their inten- EGK Dark Site Committee: tions known to a DAS board member. Wayne Kaaz (Chair) (303) 840-1549 Email: [email protected] We are starting a new project within the scope for use. Interested members IDA Representative: DAS, to design and build a complete should contact Ron Pearson or any Dr. Robert Stencel Public Outreach Committee: telescope around the excel- other board member. Ron Mickle (Chair) lent 17.5-inch mirror I’m keeping this month’s column Bryan Wilburn (External Outreach Coordinator) Email: [email protected] (303) 542-5137 and diagonal we own. short to be able to include a list of DAS Student Astronomy Committee: This effort is to make a 2008 events for your refrigerators. See Naomi Pequette ( Chair) great telescope, not to Page 7 for details.—Wayne Green Volunteers or Appointed decide where we deploy Representatives ALCor: Jerry Sherlin Email: [email protected] (303) 680-6894 JANUARY FEBRUARY IDA Representative: (International Dark Sky Association): Dr. Robert Stencel 1 New Year’s Day (No Public 9-10 EGK Dark Site Weekend Newsletter: Night) 16 Open House at Chamberlin Observer editor, Patti Kurtz 5-6 EGK Dark Site Weekend Observatory (Begins at 5:00 P.M.) Email: [email protected] (720) 217-5707 12 Open House at Chamberlin 20 Lunar Eclipse Open House at Observer proofreaders: Darrell Dodge and Steve Solon The Observer is available in color PDF format from Observatory (Begins at 5:00 P.M.) Chamberlin Observatory (Begins at the DAS website. 18 General Membership Meeting at 5:00 P.M.) Website: D.U.’s Olin Hall (Begins at 7:30 P.M.) 22 General Membership Meeting at Darrell Dodge DAS Information Line: 25 E-Board meeting at Chamberlin D.U.’s Olin Hall (Begins at 7:30 P.M.) (303) 871-5172 Observatory (Begins at 7:30 P.M.) 29 E-Board meeting at Chamberlin DAS Correspondence: Observatory (Begins at 7:30 P.M.) Denver Astronomical Society Chamberlin Observatory C/O Wayne Green 2930 East Warren Avenue Public nights are held every Tuesday and Thursday evenings beginning at the following times: Denver, Colorado 80210 March 9 - April 14 at 8:00 P.M. April 15 - September 1 at 8:30 P.M. The Executive Board conducts the business of the DAS at September 2 - March 8 at 7:00 P.M. at Chamberlin Observatory 7:30 P.M. at Chamberlin Observatory. Please see the Costs to non-members are: $3.00 adults, $2.00 children. Schedule of Events for meeting dates. All members are Please make reservations via our website (www.thedas.org) or call (303) 871-5172. welcome.

DAS Schdule thedas.org

Page 2 The Denver Observer January 2008 Renowned Artist, Michael Carroll, Speaks to the DAS in January by Keith Pool

ur guest speaker for the January 18th coauthored over a OGeneral Meeting will be Mr. Michael dozen books on Carroll. Carroll has been an astronomical, topics ranging from science fiction and paleo artist for more space to geology than two decades. He has done work for and biology. His NASA and the Jet Propulsion Laboratory. book Alien Volca- His art has appeared in several hundred noes (John Hopkins magazines throughout the world, includ- University Press) is ing Time, National Geographic, Scientific due out in June American, Asimov’s, Smithsonian, Astronomy, 2008. Carroll will Sky & Telescope, Ciel et Space, and Astronomy be signing his new- Now (UK). His paintings have aired on est book, Space Art: Nova, National Geographic’s Explorer, and Drawing and Paint- other television specials and have been ex- ing Planets, Moons hibited throughout the world. Carroll is a and Landscapes of Fellow and founding member of the Inter- Alien Worlds at the national Association for the Astronomical General Meeting. Arts. He is the 2006 recipient of the Lucien Come join us as Michael Carroll explores invited to nearby Chamberlin Observatory Rudaux Lifetime Award for contribution the wonders of volcanoes on other planets for refreshments, conversation, and to the astronomical arts. One of his paint- and moons. From the more familiar forms weather permitting, views through the 20- ings is currently on its way to Mars (in digi- of erupting mountains on terrestrial worlds inch refractor. tal form)—aboard the Phoenix Lander. to the truly alien cryovolcanoes of ice and In addition to painting, Carroll is a popu- liquid gas, Carroll shows us—through pho- lar science author, writing for such maga- tos and paintings—the latest discoveries at zines as Astronomy Now, Popular Science, Mars, Saturn and Venus. Astronomy, Sky and Telescope, Odyssey and As always, the general meeting begins at The Artists magazines. He has authored or 7:30 P.M. and is held in Olin Hall’s room 105 on the University of Denver’s cam- pus. There is a fee for parking in the lot adjacent to the building, but there is usu- ally available street parking nearby if you don’t mind a short walk. Afterwards, all are

Michael Carroll (above right). His extraordinary work has graced the covers of numerous magazines and aired on television specials—his exhibitions are known worldwide. Two of his paintings (left and right) are published here with his permission.

updates

January 2008 One Mile Nearer the Stars Page 3 Image(ine) That Part Three Article and Images by Steve Solon

t this point in our imaging journey, this is supposed to be enjoyable. Along Ait’s likely that the seat of your pants those lines, though, while there will be may be a bit frayed and you’re out of tea; some “zooming-in” to check details dur- you’ve spent quite some time at the com- ing the course of final processing, as a rule, puter. One trade off is that you’re moder- you’ll view your final work from at least a ately clear-headed, a condition that work- foot away when all is said and done—don’t ing with pungent film chemicals will not go crazy over dust-sized specks. leave you in. Many of the tools we’ll use in Adobe Let’s review the process thus far in steps. Photoshop® require experimentation— You’ve: we’ll cover the basics, but play around with 1.) Created as stable an imaging plat- The “Fits Liberator” plug-in allows the different settings. Don’t forget to ask form as possible, Photoshop® to work with FITS files. questions of imaging friends; these are 2.) Taken exposures of 30 seconds or works-in-progress, after all. longer for a better S/N ratio, separate folder and aligned that The folks at the European Southern Ob- 3.) Assembled good sets of reduction folder. servatory and the Space Telescope Science images: darks, flats, flat-darks, It’s time to assemble all this work into an Institute released to the public a plug-in 4.) Aligned the reduced images, image that will give you great satisfaction. for Photoshop® some time ago that is used 5.) Examined each aligned image for Remember that what you produce is up to to process Hubble images. It’s called “Fits quality, deleting the poor ones, you. I know several folks who’ve gone gray Liberator” and can be downloaded for free 6.) Saved the combined images (L or H- trying to get their images absolutely per- at: spacetelescope.org/projects/fits_liberator. alpha, R, G and B) as FITS files in a fect under close scrutiny with a microscope; This program allows Photoshop® to work with FITS files, something previously not possible. We’ll begin with the lu- minance image in our ex- ample “7331-Stephan’s” folder, since this is where most of the detail lies. Opening the luminance FITS file activates the Lib-

War with a World During a period in the solar system’s history known as the “Late Heavy Bombardment,” some 3.9 billion years ago, our celestial companion sustained 95 percent of the impacts we see today. Were it not for Earth’s active geology, biology and weather, this tortured surface might easily resemble our own. Steve captured Luna with 30 frames at .01 seconds per frame through a Custom Scientific 4.5 nanometer h-alpha filter. observers deck

Page 4 The Denver Observer January 2008 erator plug-in (above left.) This wonderful mind immediately after the fact, click tool supports an advanced histogram that Edit>Undo Unsharp Mask. Use the Zoom allows you to manipulate brightening and tool (magnifying glass icon) and zoom in darkening over a greater range than other a few times to check stars for over-defined programs. On the right side of the win- edges, shadowing, and a flattened appear- dow, check the boxes labeled White clip- ance, signs of too much sharpening. By the ping and Black clipping. As you “stretch” way, right-clicking with the Zoom tool your image, these will keep you out of the engaged allows quick zooming and image maximum danger zones. Under Stretch size functions. Function, I like working with the setting Keep in mind that sharpening, like most AsinH—it offers the greatest flexibility for of the processing functions, can be applied me, but experiment with the different set- to only part of an image, if desired. Use The Channels Box tings. You’ll also want to try the Back- the Lasso or Marquis tools to draw around ground level and Peak level functions by an area you’d like processed a bit more— you’ve shot your color images at a lower clicking on the icon to the right of the fig- in the case of our example image, perhaps bin rate. You can either resize each color ure window. Now, adjust your sliders in the some of the detail in 7331’s spiral arms. image individually or after they’re com- window under the image—get used to the Start with the above Unsharp Mask set- bined. Also, color images contain much touch of “just right”, but remember, you tings and experiment. Do the same for the less light data than luminance images— can always start from scratch if you don’t of Stephan’s Quintet. After sharp- sharpening them would create havoc. In- like the results. Moving the white slider to ening an area, use the Blur tool to smooth stead, apply a mild Gaussian Blur by click- the right can significantly reduce burned the edges. If you should get several pro- ing Filter>Blur>Gaussian Blur and select- galaxy cores and overly bright nebulosity. cesses down the road and decide you don’t ing a Radius of 1.5 pixels. Essentially, all Click OK when finished and the image will like a particular function you’ve used, you we want out of these images is their color. be imported into Photoshop®. “Fits Lib- can get rid of it. Click Window>History, Save the finished images as TIFFs erator” tends to flip your image vertically; highlight the mistake function and click Combine your color images as a group correct this by clicking Image>Rotate the trash can icon. first. Open your red, green and blue TIFF Canvas>Flip Canvas Vertical. Use the other various histogram func- images (all previously aligned, hopefully.) To create a color-combinable luminance tions carefully to change brightness levels. Click Window>Channels—the box above image, you must first change the lum’s Image>Adjustments>Levels allows the appears. Click the arrow at the top right mode. Click Image>Mode, highlight RGB changing of different pixel brightness corner, select Merge Channels and change color and change from 16 to 8 bits per chan- groups. Image>Adjustments>Brightness/ the Mode to RGB Color, making sure nel. Contrast applies general brightening and there are three channels—if not, check the Resizing is the next step. CCD images contrast levels to the entire image. Experi- Bits per channel of each of the color im- are typically large in size, but small in the ment with Curves, as well, to brighten dim ages under Image>Mode—one may have dots-per-inch category. Click Image>Image areas. been changed to 8 (computer gremlins)— Size, be sure that Constrain Proportions At this point, get up and walk away from change it back to 16. Click OK and check is checked and change your Width to 8 your work—this break restores your vision, that the file names match, then click OK— inches—Height will automatically ad- sanity and sense-of-self away from the im- there is your color combination, which can just—and change your Resolution to 300 age. Upon your return, make a few more be manipulated in a thousand ways. As a pixels per inch. Now you have the begin- adjustments, save the image as a TIFF and rule, the image will be fairly dim; carefully nings of an image that will be suitable for minimize it. add some Levels or Curves brightening moderate-size printing. Perform the above work on your reds, to bump things up. Save the image as a Sharpening is a tool that can be badly greens and blues—with some differences. TIFF file—“7331 color combine” or overused, so begin carefully. Apply a mild Photoshop® will automatically change the something similar. Unsharp Mask to the entire image by click- Mode and Bits per channel of the color To mate it with your minimized lumi- ing Filter>Sharpen>Unsharp Mask. Start images when they’re combined, so there’s nance, click Select>All—an animated mar- with an Amount of 50%, a Radius of 1.5 no need to perform these corrections. quis forms around the edge—then click pixels and Threshold of 10 levels—watch Resizing is necessary, however, to match Edit>Cut; your image will disappear. No the preview window to see the results— aspect ratios with the luminance you’ve just click OK when finished; if you change your finished. This is especially necessary if Continued on page 6 observers deck

January 2008 One Mile Nearer the Stars Page 5 Image(ine) That 100%, click the Normal box down-arrow (continued) and select Color at the bottom. This blend- ing mode renders stars a more lifelike color Continued from page 5 and gives greater flexibility in adjustment. Experiment with the other blending modes worries—it’s gone to the Clipboard; close just to see their properties. At this point, the blank window. Bring up your lumi- save the image as “7331 composite”—it nance image and click Edit>Paste. Your will be saved as a “PSD” (Photoshop® color image appears with no sign of the REDDocument) because GREEN it contains layers. As luminance. The reason is that you’ve cre- you continue with manipulating the im- ated two layers—the color, on top at full age, periodically save it. opacity, and the luminance buried under- The Layers Box Now, comes the experimentation. Too neath (labeled “Background.”) We’ll fix many possibilities are available to list that by showing both layers and adjusting have only a few stars in the image and click here—trial and error is the best way to them. Click on the Layers tab. You can Edit>Free Transform. Your cursor becomes learn. For starters, though, Levels, Curves change the “Layer 1” to “7331 color” by a small arrow and clicking and dragging it and Brightness/Contrast will be the pri- right-clicking on the image to the left of moves the color layer over the luminance— mary functions for bringing out faint de- “Layer 1” and clicking “Layer Properties”— make sure that things line up the way they tails. Other basic tools you’ll use, also un- BLUE LUMINANCE change the name and click OK. Click the should. Several pressings of your keyboard’s der Image>Adjustments, are: Color Bal- Opacity arrow and move the slider to arrow keys will move the color layer in small ance, Hue/Saturation, Selective Color, 50%— both layers are now visible and it’s increments for fine aligning. When fin- Channel Mixer and Shadow/Highlight. a good idea to check your alignment, just ished, double click in the image to apply Experiment with too much red and too to be sure all is well. Zoom in until you the transformation. You can apply a Free little blue, desaturate the magentas and Transform as often pump up the yellows. Apply changes care- as you like, as long as fully. This is where your creativity, knowl- you have not Flat- edge of the target and artistic whim com- tened the image. bine to produce the final outcome. . . your Once you are accu- image. When you’ve finished (and who is rately aligned, crop- ever really finished), click Layer>Flatten Im- ping and resizing the age. Your work can now be saved as a TIFF entire image can be for printing or JPEG for sharing via email performed, although and you’ll still have your original PSD to I recommend saving work on again as you learn. this until you’re a bit For more information, a terrific resource further down the is Ron Wodaski’s book, The New CCD As- processing line. tronomy” © 2002 New Astronomy Press. A trick to getting Even though the publication is now six better, truer color is years old, it continues as a wonderfully to change the blend- applicable manual for this ever-changing ing method. In the medium. Be aware, though, that it is Layers box, move printed in black and white, yet there are your opacity back to references to the color in some images. Also, you’ll find many of the image Figure num- bers are out of sequence. The Horsehead Enjoy your images and the process of (NGC learning—never-ending, it is. 2024) in Orion (left). Questions always at: [email protected] Steve made this RGB image with the * Photoshop® windows reprinted with permission— StellarVue SV- ©2000, Adobe Systems® 80mm—80:30:40 * FITS Liberator window reprinted with permission— minutes, respectively. ©2005, ESO, ESA, STScI observers deck

Page 6 The Denver Observer January 2008 Photo © 2007 by Joe Gafford

The Galaxy (M31) with elliptical galaxies NGC 205 (above it) and M32. This image is a mosaic of 15 images taken at the Okie-Tex star party and the EGK Dark site from October through November, 2007. An SBIG ST-2000XM ccd camera was used on a 10-inch f/4.5 Newtonian. Each image is a stack of 20/20/15/20 minutes of LRGB for a total of more than 20 hours of exposure time due to a redo of a few color frames. An older, less saturated image of M31's core was stacked on for detail. This was Joe’s first field test of his 10-inch with a new tube assembly that has internal armature bands to stiffen it for heavy ccd cameras. As a result, this is Joe’s deepest image to date of anything he’s taken due to better tracking. January Skies (continued) etary happening is the conjunction of Ju- piter and Venus at the end of the month. Continued from page 1 The pair are at their closest on the early The next two nights, January 2 and 3, morning of Monday February 1, a photo- Tuttle passes to the right of that mysteri- op that happens in the last bit of darkness ous seldom-seen Aries. Find before dawn. Mythologists may wonder the Seven Sisters; Aries is a curved line of what’s going to happen when these two stars between them and the comet, closer powerful personalities get together in the to the comet. A Tuttle day farther south sky! the comet passes the spiral galaxy M74 as Meteors: the Quadrantids peak January it cruises down the left half of the giant V 4 just after midnight; start looking for them of . By January 9 the rapidly-dim- about 11 P.M. The January Astronomy (page ming Tuttle is just west of Mira in Cetus. 53) says it is a strong shower with an hourly After that it should drop into the murk rate of 120 meteors. That’s two per minute. near the horizon. The radiant of this shower is in the north- Mars will also be dimming as it pulls east. away from Earth, but a bright object all I believe that the theme of this month’s month, closer to Auriga than to Gemini as Open House on the 12th is Mars Madness. the month wears on. Its 15-arcsecond disk Some of us are already over the line, how- may yield details to the patient observer ever: I will be out on the field seeing how who waits for those moments when the sky many possums will fit into the tube of my Key to above calendar: GM = General Meeting settles down along her line of sight. If you’re dob—even though the manufacturer says OH = Open House doing a planetary night Saturn comes into never, never do this! But don’t worry, these DSW = Dark Site Weekend view after midnight, in Leo. Another plan- are fun-loving possums.—Dennis Cochran EB - Eboard Meeting observers deck

January 2008 One Mile Nearer the Stars Page 7 About the Denver Astronomical Society APPLICATION FOR MEMBERSHIP TO THE Membership in The Denver Astronomical Society is open to any- DENVER ASTRONOMICAL SOCIETY New Renewal one wishing to join. The DAS provides trained volunteers who host Name: educational and public outreach events at the University of Address: Denver’s Historic Chamberlin Observatory, which the DAS helped City, State, Zip: place on the National Register of Historic Places. First light at Cham- Phone numbers: Home ( ) Work ( ) berlin in 1894 was a public night of viewing, a tradition the DAS has E-mail Address: Occupation: helped maintain since its founding in 1952. Other Interests: The DAS is a long-time member in good standing of the Astro- (Students Only) School: Grade: nomical League and the International Dark Sky Association. Do you want to download the newsletter in PDF format from our The DAS’ mission is to provide its members a forum for increas- website instead of by postal mail? ing and sharing their knowledge of astronomy, to promote astro- Yes No Do you want the above information excluded from the yearly roster? nomical education to the public, and to preserve Historic Cham- Yes No berlin Observatory and its telescope in cooperation with the Uni- Please Circle All That Apply: versity of Denver. Regular Membership: $35 Students: $12 (Students under age 23) $ The DAS is a 501(c)(3) tax-exempt corpo- Astronomy Magazine/$34 and/or Sky & Telescope Magazine/$32.95 $ ration and has established three tax-deduct- Van Nattan Scholarship Fund $ Public Outreach Fund $ ible funds: the Van Nattan-Hansen Scholar- DAS Dark Site Fund $ ship Fund, the Public Outreach Fund, and Total Amount Paid $ the Edmund G. Kline Dark Site Fund. To con- Please send all checks to Brad Gilman, DAS treasurer, 7003 S. Cherry St., Cen- tribute, please see the bottom of the member- tennial, CO 80122-1179. Please make donations to the DAS Dark Site with a separate check, payable to the "DAS Dark Site Fund." For DAS Membership ship form for details. and other funds, including new-member magazine subscriptions, please make More information about the DAS, its activities, and the special amounts payable to the "Denver Astronomical Society." DAS RENEWALS tax-deductible funds is available on the DAS web site at ONLY: you may now send your Sky & Telescope subscription funds directly to www.thedas.org. the magazine's subscription service, using the renewal form sent to you.

Denver Astronomical Society c/o Chamberlin Observatory 2930 East Warren Avenue Denver, Colorado 80210

join us Page 8 The Denver Observer January 2008