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February 2016 Observer

February 2016 Observer

The Denver FEBRUARY 2016 OBSERVER

Comet C/2013, US10 (Catalina), a recent visitor to the inner solar system, in local skies on a rare cloudless night... Image © Ron Pearson

FEBRUARY SKIES by Zachary Singer

This month, we’ll check out an easy but worthwhile binary, an ex- in the dawn sky, about 5°, on average, to the right and upward from emplary open cluster, and for experienced observers, a truly “far-out” Mercury when you look eastward. As the month goes by, Venus will globular cluster. But first, a quick stop at our solar system… also move closer to the , finishing February about 25° to the Sun’s west. Local Sky At the same hour, Saturn shines in the south-southeast at Febru- As we head into February, dawn comes ever earlier, and the lazy, ary’s beginning, and ends the month in the south. Outshining nearby “after 7” sunrises of the month’s opening days will give way to sunrise by at least ½ closer to 6:30 a.m. For the first half of the month, though, getting up magnitude, Saturn will Sky Calendar early will still get you a view of all the naked-eye planets—Mercury be easily identified. 8 New Moon through Saturn—in the same sky. (We’ll do them in order of view from (Keep in mind, though, 15 First-Quarter Moon east to west.) that by month’s end 22 Full Moon In the Observer Nearest the Sun’s glow, you’ll need to look for (Mar 1) Last-Quarter Moon Mercury shines at mag- this planet earlier in the President’s Message ...... 2 nitude 0, but only about morning to keep the 5° above the southeastern dawn from spoiling a telescopic view.) Society Directory ...... 2 horizon at 6:15 a.m., at the Mars starts February in the south at 1st magnitude, and brightens Schedule of Events...... 2 beginning of the month. about a ½ magnitude by the beginning of March. Even then, though, DAS News ...... 3 It draws closer to the sun it’s still only half the angular diameter it will have at opposition in late as the days progress, and May, so stay tuned. Meet a DAS-er...... 3 will be lost in solar glare And finally, there’s Jupiter! Only a month away from opposition, it’s About the DAS...... 3 by mid-month. (A much now both a “morning” and an “evening” object—transiting at around a Getting Your Bearings...... 4 better look at this planet is quarter to 3 in the morning in the first days of February, it crosses the coming in the spring.) Meridian not long after midnight when March begins. That puts it in Venus blazes at -4 mag. the southwest morning sky early in the month, and very low in the west Continued on Page 6 THE DENVER OBSERVER FEBRUARY 2016

Society Directory PRESIDENT’S MESSAGE by Ron Hranac DAS Executive Board DAS Elections—Get Involved! President: Ron Hranac It’s that time of again: Have you renewed your Denver Astronomical Society membership? president@denverastro .org Notices were sent out last month, and the good news is the number of renewals is on track with this Vice President: same time last year. Thanks very much to those of you who have renewed to support DAS and as- Stuart Hutchins vp@denverastro .org tronomy for 2016. If you haven’t yet done so, the following link will take you to our renewal web Secretary: page, where you can use either PayPal or a credit card. (A PayPal account isn’t necessary.) http://www . Jeff Tropeano denverastro .org/dasrenew .html . secretary@denverastro .org Denver Astronomical Society’s success as an organization depends largely on the many volunteers Treasurer: who fulfill a variety of roles. Among those roles are outreach and sharing our love of the and Michael Nowak treasurer@denverastro .org night sky with the public—think monthly Open Houses, twice-weekly Public Nights, and activities at Executive Board Members: museums, schools, and other venues. Another important role that often takes place behind the scenes Johnny Barela Ed Scholes is leadership of the Society. Our annual elections are upon us, and I’d like to invite you to consider Jack Eastman Sorin Joe Gafford Ken Sturrock tossing your hat in the ring for a position on the Executive Board—otherwise known as the E-Board. Chuck Habenicht Dan Wray At the very least, cast a vote in this month’s elections. Past President, Ron Pearson Article II, Section 2.0 of Denver Astronomical Society’s bylaws says, “The Annual Meeting and President Emeritus, Larry Brooks election of the Executive Board and Officers shall be conducted at the General Meeting in February or Committees at another date, as the Executive Board may direct. The Officers and Board members will be installed Van Nattan-Hansen Scholarship Fund: at the Annual Banquet in March.” Ron Pearson (Chair) th PO Box 100621 This year’s annual meeting is scheduled to be held on Friday, February 19 at DU’s Olin Hall, with Denver, CO. 80250-0621 things getting underway at 7:30 p.m. MST. EGK Dark Site Committee: You’re encouraged to attend the annual meeting and participate in the elections. Keep in mind that Darrell Dodge, Interim Chair darksite@denverastro .org elected officers and board members are your voice in the direction of DAS, so let your voice be heard. Nominations began at the general meeting in January and will continue through February’s meeting. IDA Representative: Dr. Robert Stencel If you’d like to nominate someone (including yourself) for a position on the E-Board, send an e-mail coloida@hotmail .com to nominations@denverastro .org, or let Tim Pimentel know in person. Volunteers or Appointed Following the elections, the new leadership will get busy planning another exciting year for DAS Representatives members and the public. If you have comments or suggestions, feel free to contact any of the E-Board : members. We welcome your input. Our next major membership event is the DAS Spring Banquet on Darrell Dodge 303 932-1309 Saturday, March 19th; I hope to see you there! Newsletter Editor: Continued on Page 5 Zachary Singer 303 718-4188 editor@denverastro .org Newsletter Proofreaders: DAS SCHEDULE Darrell Dodge, Ron Hranac The Observer is available in color PDF format from the DAS website . Website: Darrell Dodge FEBRUARY 2016 webmaster@denverastro .org IT Coordinator: Ken Sturrock itdept@denverastro .org 13 Open House—DU’s Historic Chamberlin Observatory—Starts at 5:30 PM External Outreach Coordinator: 19 Annual Meeting at DU’s Olin Hall, Rm. 105, 7:30 PM—Featured Speaker: Alan Erickson, Julie Candia who will discuss astro-imaging with DSLRs (see “DAS News”); DAS E-Board Elections external@denverastro .org 26 E-Board Meeting—At DU’s Historic Chamberlin Observatory, 7:30 PM Public Night Coordinator: Hugh Davidson 303 679-0629 Librarian: Phil Klos During Open House, volunteer members of the DAS Public Nights feature a presentation on astronomical DAS Information Line: bring their telescopes to the Chamberlin Observa- subjects and a small-group observing session on the (303) 871-5172 tory’s front (south) lawn, so the public can enjoy historic 20-inch telescope (weather permitting), at Cham- DAS Correspondence: views of the and planets, try out different berlin Observatory on Tuesday and Thursday evenings Denver Astronomical Society telescope designs, and get advice from DAS mem- (except holidays), beginning at the following times: bers. The Observatory is open, too (costs listed P.O. Box 102738 March 10 - September 30 at 8:30 PM Denver, Colorado 80250 below), and its historic 20-inch telescope is open president@denverastro .org for observing with no reservations necessary. October 1 - March 9 at 7:30 PM Open House costs (non-members): If the skies are clear, Public Night costs (non-members): $4/adult, The Executive Board conducts the business of $2/person ($5/family), $1/person in inclement weather. the DAS at 7:30 p .m ., at Chamberlin Obser- $3/child and students with ID. DAS mem- DU students with ID, and DAS members free. vatory . bers and DU students with ID: free. Please see the Schedule of Events for meeting Members of the public (non-DAS/DU, as above), please dates . All members are welcome . make reservations via our website http://www .denverastro .org (www .denverastro .org) or call (303) 871-5172.

The Denver Astronomical Society One Mile Nearer the Stars Page 2 THE DENVER OBSERVER FEBRUARY 2016 DAS NEWS MEET A DAS-er Volunteer Opportunities Connor Bray, Van Nattan-Hansen Scholarship Recipient *** Please note that Lindsey Shaw has passed the baton for managing Volunteer Outreach to Julie Candia. Lindsey did an awesome job, and the DAS is very thankful for all her work . —Ed . By Dena McClung

February 13, 5:00PM-8:00PM: in Denver. Night observing for ap- Meet Connor Bray, one of two recipients of the Van Nattan- Night Observing at Heritage Cen- proximately 65 students. They are Hansen scholarships for 2015. He recently began his freshman ter in Georgetown, CO, for their interested in locating year at the Colorado School of Mines in Golden. Cultural Arts Program. Denver in the night sky. At age 15, Connor is one of DAS’ youngest members and Museum of Nature and Science will To volunteer, please contact Julie an apprentice operator at Chamberlin Observatory, which is just also be providing their Titan Virtual Candia at external@denverastro .org— two blocks from the home where he lives with his parents and Arts Program. and thanks! younger brother. He has a robust intellect, a sharp wit, and an February 18, 6:00PM: Astron- eagerness to help that made him fun to interview. omy Night at East High School ∞ Connor’s parents realized early on that he was not an aver- age child. As a toddler, he required a lot more stimulation than February Speaker the toys made for his age provided. He was reading and using a Alan Erickson, Senior Com- Photoshop, Illustrator, and Light- computer at age two. puter Scientist at Adobe Systems room. Photoshop areas include ani- At age three, Connor began attending the Ricks Center for and a DAS member since 2000, will mation, video, image selection, and Gifted Children at the University of Denver, where he could be talk about getting started in astro- image adjustments. He started imag- given challenges appropriate for his active and demanding mind. imaging with a DSLR and a camera ing in 2003. He liked Ricks because its structure met his needs and offered lens or telescope, at the DAS An- Since 2008, Alan has combined him the ability to take selected classes at a higher grade level nual Meeting, Feb. 19th at 7:30 PM, his hobby with his profession, rep- than his Ricks Center peers. Students were expected to do more in Rm. 105 of Olin Hall on the DU resenting Adobe at astro-imaging than simply complete course work; they also had to show a deep campus. His presentation includes conferences. Alan has presented analytical understanding of the material, initiative, and innova- an overview of processing software Photoshop topics at the Midwest As- tion. Towards that goal, one of his teachers graded on a scale and techniques, as well as resources tro-Imaging Conference, Advanced of twelve, rather than ten, using the two highest marks to rate for imagers. Imaging Conference, Northeast As- students who exceeded the norm. Alan has developed features for tro-Imaging Conference, and Texas Connor became interested in astronomy and science at age Party. four and a half. Finding cartoons boring, he watched shows with After the meeting, all science themes. His parents began taking him regularly to the those present are invited Denver Museum of Nature and Science, where he spent count- to a reception at DU’s less hours playing with the erosion, impact crater, rover, and Historic Chamblerlin Ob- shuttle exhibits. He went to all of the planetarium exhibits, 60 servatory, where refresh- Minutes in Space, and space camps. ments will be served. Five ago, Connor began attending the Center for Bright Some of Alan’s im- Kids during the summer. The last two summers, he has been in ages, like the one at left, the Luminary classes, which are for high school-aged students— may be viewed at https:// they cover the equivalent of a college semester of material in a alanerickson .smugmug . mere three weeks. Connor has taken classes there on computer The Andromeda , M31. © Alan Erickson com/ . ∞ Continued on Page 5 ABOUT THE DAS Membership in the Denver Astronomical the International Dark Sky Association. The mund G. Kline Dark Site Fund. Society is open to anyone wishing to join. The DAS’s mission is to provide its members a More information about DAS activities DAS provides trained volunteers who host forum for increasing and sharing their knowl- and membership benefits is available on the educational and public outreach events at the edge of astronomy, to promote astronomical DAS website at www .denverastro .org. University of Denver’s Historic Chamberlin education to the public, and to preserve His- ∞ Observatory, which the DAS helped place on toric Chamberlin Observatory and its tele- the National Register of Historic Places. First scope in cooperation with the University of light at Chamberlin in 1894 was a public night Denver. of viewing, a tradition the DAS has helped The DAS is a 501 (c)(3) tax-exempt corpo- maintain since its founding in 1952. ration and has established three tax-deductible The DAS is a long-time member in good funds: the Van Nattan-Hansen Scholarship standing of the Astronomical League and Fund, the DAS General Fund, and the Ed-

The Denver Astronomical Society One Mile Nearer the Stars Page 3 THE DENVER OBSERVER FEBRUARY 2016

GETTING YOUR BEARINGS ... from the editor and the Milky Way

y Way ilk M MERIDIAN

Auriga

Castor

Pollux

M35 Gemini Pleiades Cluster Taurus (M45)

Cancer Alhena

Canis Minor ay W y k il M

Monoceros

Rigel

View of Denver's southern sky at 9:00 p.m. in mid-February. Center of Telrad circles is about 70° above southern horizon. Object positions, constellation and meridian lines charted in SkySafari, and then enhanced. This month, our “official” target is the constellation Gemini, “The Gemini Twins! Alhena will be right there, and and will Twins,” but if you take a quick peek at our chart, you’ll see some- be obvious to you—they’re at the end of a line with Betelgeuse on the thing interesting—the band of the Milky Way, littered with deep-sky opposite end, and Alhena in the middle. When you first find Gemini in objects… Though the “Monthly Skies” column can’t cover them all, dark skies, its 4th-magnitude-and-brighter outline will be easy, too— getting a handle on what’s going on there will make it easier to visual- many of the stars are even visible in suburban skies under reasonable ize the why of deep-objects’ locations, making our galaxy both more conditions. wondrous and more understandable at the same time. Between the outlines of Orion and Gemini lies the great glowing Gemini’s outline is meant to be evocative of twin brothers from band of the Milky Way. Unlike the summer months, when we look to- ancient Greek myths; each brother is represented by a fairly straight ward our galaxy’s center, this view looks more or less outward—if the line of stars that curve just enough to suggest the hips and shoulders of summer view is towards “downtown,” this view is toward the “sub- human forms. Each also has an unmistakable 2nd-magnitude star at its urbs.” That’s actually an important distinction, as different processes head, named for a twin: . Once you’ve seen where mold these regions. Take our “downtown vs. suburbia” metaphor a this bright pair is, it will be easy to spot on its own. An equally bright little further, and consider how the intense concentration of people star, Alhena, marks Pollux’s foot. and money alters the society—and architecture—in a real city’s down- To find Gemini before you’re familiar with it, start at Orion (which town, and how the spread-out nature of the newer ’burbs has its own we covered in this column last month—if you missed it, http://www . effects; now think about the concentrated , gravity, and altered denverastro .org/das/denver-observer/). Look at (the bright star space-time at the center of our galaxy and the lower densities of mate- in Orion’s foot, at lower right), then move diagonally through the belt rial in its arms… (to the northeast), and continue until you’re at the bright orange star, The Milky Way’s “downtown” view shows us denser, older popu- Betelgeuse, Orion’s shoulder. Keep going about the same distance as lations of stars, both at its center and in the tightly packed globular from the belt to Betelgeuse, and you’ll find yourself at the feet of the (ball-like or spherical) clusters that it. Continued on Page 8

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∞ THE DENVER OBSERVER FEBRUARY 2016

President’s Message Continued from Page 2

While on the subject of DAS business, we have two openings on the Van Nattan-Hansen Scholar- ship Committee. If you’re interested in serving on the VNH Committee, drop me a note at presi- dent@denverastro .org. More information about our scholarship program is available at http:// www .denverastro .org/das/das-scholarships/. As most of you know, S&S Optika, run by our long-time friends Tim and Cathie Havens, served the Denver area for 43 years. Sadly for us, they re- tired late last year and moved to New Mexico. The E-Board decided to get them a going-away gift, in part to say thanks for all they did for amateur astronomy over the years. We also wanted to get them something to remind them of Colorado. Af- ter considering several ideas for a suitable gift, we went with something that is uniquely Colorado and astronomy-themed: DAS member Roger Clark is a photographer extraordinaire, and we chose one of his gorgeous prints of the Milky Way looming over Colorado’s Maroon Bells. The accompany- ing photo shows Roger presenting the going-away Cathie and Tim Havens with Roger Clark. Image © Ron Hranac gift to Tim and Cathie. ∞

Meet a DAS-er Continued from Page 3

coding, applied math, general physics, become an aerospace engineer with NASA astrophysics, and computational phys- or another organization in the field of space ics. exploration. In 2013, Connor transferred to Lit- But Connor isn’t all work and no play. tleton High School, where he exhausted He and his family spent some time in Hawaii their math and science offerings in two last summer, they visit family in Michigan years. While there, he also took an in- almost yearly, and he likes tinkering with dependent study college level number Linux and playing Kerbal Space Program. theory class. KSP is a space-flight simulator in which Having grown beyond the usual sec- the players build and fly simulated space- ondary school coursework, Connor and craft; its complexity can make the game his parents decided to forego having quite challenging, but it has been praised him earn a high school diploma. After for making difficult concepts of spaceflight taking the ACT test, he was accepted accessible. at the Colorado School of Mines and For Connor, that’s entirely appropriate. began taking classes in August. In ad- dition to the VNH scholarship, Connor recently accepted a NASA scholarship ∞ that includes a mandatory ten-week summer internship at one of their facili- ties. He is working toward a degree in Engineering Physics, and would like to

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∞ THE DENVER OBSERVER FEBRUARY 2016

HR 2935 NGC 2419 / Intergalactic Wanderer DU Lyncis

Omicron (ο) Geminorum MERIDIAN Castor

ay W y k il M Pollux M35 Gemini NGC 2158

Taurus

Propus

Aldebaran

Alhena

ay W y k il M Orion Procyon Betelgeuse

Looking southward from Denver at 9 p.m. in mid-February; deep-sky objects are plotted to mag. 11. Note "Telrad" placed over Meridian for reference; its center is about 75° above local horizon. Telrad circles are 4° and ½° (2° circle omitted for clarity). Object positions, constellation and meridian lines charted in SkySafari, and then enhanced. February Skies Continued from Page 1 (but visible) at the end. The planet rises before 9 p.m. in early Febru- together, each group the system’s combined center of mass. ary, and is already more than 30° up at that hour by month’s end. As they say on late-night TV pitches, “But wait, there’s more!” About 70” to the southeast (a heading of 165° from Castor), you’ll find Deep Sky a magnitude 8.8 “.” It’s in quotes because, like the stars of Our first stop after leaving the solar system is Castor, or Alpha the main pair, this star (known as “Castor C”) is also a spectroscopic (α) Geminorum, at 7h 36m, +31° 51’. It’s easily located when you binary—both of its components are red dwarfs. Castor C is unfamiliar look for the brighter of a noticeable angled pair of stars “up and to the to most observers, and it could be confused with another nearby star left” of Orion—the other star is Pollux, and together they are thought (a binary with a wide separation), perhaps making it best for the more of as the “heads” of the Gemini Twins. (If you’re not familiar with experienced, but the dynamics of the Castor system—six individual the constellations Gemini and Orion, see this month’s “Getting Your stars in all—is something even a newbie can marvel at. Bearings.”) Our next object, , (6h 10m, +24° 20’) in Gemini, is At first glance, Castor is a bright binary, a cool-white duo about a beautiful open cluster, something of a “classic” of its type. For the 5” apart. They’re a beautiful pair, even in small telescopes, and their beginners, a cluster of this sort is the product of a giant, star-forming separation (and the ease of splitting them) gives a useful clue about cloud like the Orion (also known as M42) that we explored current “seeing” conditions—when this pair is high up but hard to split last month. To understand M35, imagine that about 100 million years at moderate powers, then there’s a lot of turbulence in our local skies, ago, this cluster was enshrouded in a great nebula of its own, as M42 and views of detailed objects will suffer. is now, and that the stars you see were hidden within. Over time, radia- It turns out, though, that Castor has much more to it—both of the tion pressure from its stars began to blow away the nebula’s gas and main stars are spectroscopic binaries themselves. That is, the light dust, revealing more and more stars. from each comes from their own pair of stars, which orbit each other Astronomers can estimate the cluster’s age because the hottest, too closely to be seen separately from Earth. (We infer the unseen type “O” (blue) stars have already used up their hydrogen fuel, leaving companions’ presence from the way the lines in the stars’ spectra split cooler (and less blue) type “B” stars to carry the torch. Cooler, dimmer apart, then merge, and then split again in a consistent cycle.) For Cas- and yellower stars make up the rest of the cluster—as M35 ages, fewer tor, what looks like two stars orbiting each other turns out to be four of the bluer “B” stars will remain, as they burn out more quickly than stars in two groups; the stars within each group orbit each other, and their cooler cluster mates. Continued on Page 7

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February Skies Continued from Page 6 ine a line from Alhena to Propus, extend it a shade over 2°, and put When you observe M35, start out with a low-power view; this your Telrad’s center there. The Telrad’s outer edge will then be on or cluster spans more than a half-degree of sky. Then try higher power close to Propus, and M35 will be visible near the center of your find- eyepieces to check out some of the details—you may notice a few erscope’s view. At least some of the cluster should also be visible in unusually bright, orange stars within the cluster. These are “giants”— a wide, (one-degree) telescopic field. Once you’ve got M35, look ½° former hot blue stars which, having expended much of their hydrogen southwest for NGC 2158—that 1° field should include it when M35 is fuel, have gone on to fuse helium or other elements in their old age. centered; if not, a slight nudge should pick it up. (These later phases of don’t last long, so there are Our last object, as advertised, is truly “far-out”—it’s both an relatively few stars like them in the cluster.) oddball and distant. This object, NGC 2419, or the “Intergalactic Wanderer,” at 7h 39m, +38° 51’, is a dim globular cluster due north of Castor, in the constellation . If you’ve sailed the starry sea awhile, the idea of a globular in this area will likely raise an eyebrow! If you haven’t, this giant ball of stars is in a very unusu- al spot, almost 180° across the sky from where most globulars are found—you’d ordinarily expect to find them in the general direction of Sagittarius, the con- stellation overlying the center of our galaxy. Research with ever-better instrumentation over the decades paints a picture of a truly remote object some 270,000 light-years from us, and 300,000 light-years from the center of the Milky Way—that’s at least 10 times farther than the bright ones you might be famil- iar with. Earlier astronomers, while greatly underesti- mating 2419’s distance, also erroneously believed this object flies free through space (thus its nickname); the Wanderer, though, is now thought to orbit the Milky Way—about every 3 billion years! Looking at NGC 2419, it must be said, is not the same experience as viewing the great globulars, like M5 or M13. Compared to these bright (mag. 5.7-5.8), M35, the bright cluster at center, lies about 2,800 light-years from Earth; NGC 2158, easily resolved showpieces, NGC 2419 is nearly 5 the smaller-looking cluster at lower left, is more than 16,000 light-years distant. magnitudes, or almost 100 times, dimmer at mag. Image © Darrell Dodge 10.4; and even large amateur telescopes won’t show For the curious, there’s nearby NGC 2158, (6h 08m, +24° 05’), a much beyond a round fuzzy glow that would remind you of how the much older open cluster than M35. Its greater age means that even the showpieces look in a finderscope. Still, it is visible, even in small- “B”-class stars might have conked out by now, and in fact, the cluster er telescopes, and the ideas behind it, rather than a flashy view in a is populated by stars much yellower than that—the “B” stars are gone, ’scope, are the point here. (One more for the road: at the Wanderer’s as well as the longer-lasting and cooler type “A” stars. That leaves a distance, it should be closer to mag. 11 than 10, if it’s the same in- lot of type “G” stars like our Sun along with even cooler stars, and herent brightness as M13 or M5. The “extra” brightness tells us this some type “F” stars, just one class hotter than the Gs. All of these types globular is intrinsically much more luminous—2419’s actual output is are noticeably yellower and intrinsically dimmer than M35’s hotter nearly double that of M13. Ironically, this faraway globular, dimmed showboats, but they’ll be around a good long time. NGC 2158 is also by distance, is among the very brightest, intrinsically, that we know much farther away than M35 (more than 16,000 light-years from us, of.) compared to M35’s “mere” 2,800), so it’s also dimmer and smaller in If you’re good at star-hopping or your ’scope has go-to capabil- the eyepiece than M35. It makes for an interesting comparison (see ity, and you’re already familiar with globulars, the Wanderer will be photograph). worth a look—for the sheer difference in appearance, if nothing else. M35 is at the “feet” of the Gemini Twins, a constellation note- If, on the other hand, you’re lacking either the experience with bright- worthy for its roughly parallel matching “stick figures.” The “foot” er globulars or the ability to navigate to this challenging target, you’ll you want is on Castor’s side, but it’s easier to find the other foot (on likely find this more trouble than it is worth—file this one away until Pollux’s side) first—just look for Alhena, Gamma (γ) Geminorum, the you’re ready for it, and give it a proper go then. bluish 2nd-magnitude star halfway between Pollux and orange Betel- If you want to give the Intergalactic Wanderer a try, precise tech- geuse (Orion’s shoulder). Having Alhena as a reference quickly orients nique will be important, as the object’s magnitude will likely make it you to the length and direction of the “twins” figure, and makes it too dim to appear in a finderscope. If you’re not using a go-to system, easy to gauge where Castor’s foot is. the “second-best” approach is with an equatorial mount: Align Cas- In dark country skies, you’ll see M35 as a subtle glow a little more tor with the western edge of your Telrad’s innermost (½°) circle, and than 2° northwest of Castor’s foot—orange, 3rd-magnitude Propus, move directly north a little over 7°. Use the setting circles or Telrad to Eta (η) Geminorum. If you can’t see the cluster with naked eyes, imag- measure out most of the way, and sweep the Continued on Page 8

The Denver Astronomical Society One Mile Nearer the Stars Page 7 THE DENVER OBSERVER FEBRUARY 2016 Getting Your Bearings February Skies Continued from Page 4 Continued from Page 7 The “suburban” view is that of the galaxy’s wide arms—the thinner, last degree or two looking through a low-power eyepiece. outer part of the galaxy’s “flying saucer” shape—it’s home to more re- For Dobsonian users, well…. Theoretically, you could use the cent nebulae, like the Great Orion Nebula (M42) and the open (loosely equatorial folks’ trick when the Wanderer is at the Local Meridian shaped) clusters that formed within them. (due south), but it so happens that that also puts the globular very This month’s “Skies” column focuses on some of the open clusters close to the zenith, where even easy-to-see targets are a real pain for in Gemini, but take a close look at the map here, and you’ll see lots of dobs. You’ll probably be better off trying at least an hour before or small, dotted-circle symbols that stand for clusters like them; the many after that, when your ’scope will be easier to point, and star-hop the squares and cloud-shapes mark nebulae. Notice how uncluttered the hard way. top left and bottom right of our chart appear, away from the band of In that case, try hopping from Castor to 5th-magnitude Omicron the Milky Way and towards intergalactic space. (��)) Geminorum, a littlelitt le bit less than 3° away and roughly north-northnorth-north-- As a last thought, it’s worth noting that this part of the Milky Way east (see chart, p.6). From there, continue in the same direction to continues beyond the top and bottom of the chart, with even more neb- orange DU Lyncis, about 3½° beyond Omicron Gem.; it’s also 5th mag. ulae and clusters—don’t consider this map to be an exclusive list… There’s one last hop, about 1½° northwest, to another orange star, Even if you don’t explore all these objects with your telescope, I hope 6th-magnitude HR 2935—it should be obvious near the edge of your the sheer weight of their numbers leaves an impression on you. finderscope field when you’ve centered DU Lyncis. Your prize, the Wanderer, is just 2/3° to the northwest from there; a 1° field in your telescope, strategically placing HR 2935 near the appropriate edge, should include both the star and the globular. If not, keep the star ∞ near the edge of the field while you circle-sweep the ’scope around it, and the Wanderer should reveal itself. —Good luck, and see you next month. ∞

The Denver Astronomical Society One Mile Nearer the Stars Page 8

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