Hello, everyone, and my apologies for not posting more so far this year. Maybe I can make up for this in small part by relating the story of a fine and curious session this morning, starting at around 0339 PST, with Vela as the main focus. [While the first three sections of this account were written on Friday, when the session had indeed happened "this morning," the rest was only set down Monday and very early Tuesday -- but I hope that the freshness is still there, along with more details about an asterism including Lambda Velorum described by Andrie van der Linde where it is a pleasure to identify the letter names or Henry Draper Catalogue (HD) numbers of all six stars.] -------------------------------- 1. A Cosmic "Phone Call" at 0339 -------------------------------- After retiring last night before midnight, I found myself up with things still obviously still dark, and looked at the red LED alarm clock (not necessarily designed that way specifically to conserve night vision, but a nice feature) -- 0339. It was as if I had received a cosmic "phone call": quickly recalling that the local sidereal time (LST) at midnight had been about 0357, I realized that my awakening was a timely one and that I had a mission, should I choose to accept it: to explore the constellation of Vela. Among the attractions would be the brilliant Gamma Velorum system, the open cluster Trumpler 10, and a charming "alien" asterism including Lambda Velorum suggesting the head of an extraterrestrial as often envisioned with antennae. I learned of this asterism in a Sky Log for May 2007 by Andrie van der Linde of Pretoria, South Africa, made available by Eridanus Optics CC: Thanks to Andrie for a delightful presentation that gave me an irresistible desire to see that asterism, if possible: how would it look from central California, rather than the Pretoria region of South Africa or somewhere with a comparable latitude? Certainly I could see Lambda Velorum, but would all of the other five stars making up the "alien" pattern be visible? As it proved, the appropriate watchword of the morning was to be "Nit gedeiget," a Yiddish phrase freely (and almost literally) translated as "Not to worry." ------------------------------------------------- 2. In the catbird's seat: A view of Gamma Velorum ------------------------------------------------- The first question, as I got my binoculars and opened the drapes and blinds while trying to avert my eyes from local light trespass sources, was whether the sky would be overcast, clear, or somewhere in between. For observing very close to the horizon, indeed sometimes within about 4 degrees of it, "clear" would be the preferable answer. I looked out the bedroom window, saw some stars, as well as what looked like some haze or the like near the horizon -- and quickly decided to check things out with the 15X70 binoculars. The good news is that things looked reasonably clear right down to the treeline or a bit below -- as far as I could get. That, plus my dark adaptation at the ready (a nice thing to wake up with!), was the cue to start observing. First, I set up my "catbird's seat," a seat of two large pillows set one on the other, which I topped with a softer regular pillow to access a declination as low as possible. More precisely, I was seeking to access an altitude as low as possible, which would correspond with a transiting or culminating object at something like -47 degrees or a bit below that. Soon I was looking at Collinder (Cr) 140, part of an asterism in southern Canis Major that I call Ursa Austrina or the Southern Bear, with the open cluster Cr 140 as the "head" of the bear. From there I hopped to a "down arrow" asterism pointing to a "J"-shaped group of stars, with NGC 2451 just to the east. Then comes a group of stars forming a kind of "<" or "less than" sign, elongated and like a sideways V pointing to the east, converging on Zeta Puppis. Then it's a hop of a bit less than two 4.3-o fields south to Gamma Velorum. What I would emphasize is that the starhopping is delightful in itself, as well as a way to reach new or less familiar destinations. Moving between the Collinder objects, NGC 2451, and other landmarks, I joyfully reflected, "I'm really cluster-hopping" -- moving freely from one major attraction to another. There was Gamma Velorum, unmistakeable at -47d20' despite the local lights (at least not shining right into my eyes), general urban skyglow, and lots of atmospheres of intervening gases (what's the cosecant of 4 degrees or so? -- I get 14 atmospheres and a bit more from my Orpie program). ------------------------------------------ 3. Checking out the surroundings -- Cr 173 ------------------------------------------ In fact, Gamma Velorum at apparent magnitude 1.78 is actually at least a sextuple star system, also known now as Regor in honor of Roger Chafee (based on a palindrome of his first name), one of the three astronauts killed in the Apollo I fire of 27 January 1967. There the star was shining, right above the tree line -- or sometimes between the treetops, depending on my angle of view. Gamma Velorum, a wonderful sight in itself, is situated in the middle of Cr 173, a very extended open cluster which covers about 5 degrees, and thus is very nicely suited for binoculars. I could see a few stars near this brilliant Regor, although doubtless the view would be much more spectacular in darker skies. The problem isn't so much the close horizon as the lights above it! ------------------------------------------ 4. Trumpler 10 and the "New York" triangle ------------------------------------------ After moving north for awhile -- leaning back on some pillows rather than sitting upright on the catbird's seat for a look at a favorite in Puppis, M93, and its pleasant "Flowerpot with Handle" asterism -- I was back near the southern horizon to appreciate another aspect of Vela, the "New York triangle" asterism, centering roughly in the region around RA 8h40m and Dec -41-o30' or so. . NY d . . e This isoceles triangle pattern, most pleasing in its proportions and neatly fitting the 4.3-o field of my 15x70 binoculars as if it were custom tailored for this purpose, gets my chosen name from the star at the northern apex: NY Velorum, also and possibly (judging from Google) more frequently known as HD 74067. It's a Cepheid variable, the _Millennium Star Atlas_ shows, the type of variable for which Henrietta Leavitt just a century ago discovered the period-luminosity relationship which has proven a critical link in our measuring tools for cosmic distances. While she studied Cepheids in the Magellanic Clouds, thus forging concepts which would lead to the firm establishment of M31 and other spiral nebulae as external galaxies, NY Velorum is a closer stellar neighbor at about 280 light years according to one source. The other two stars in the triangle are d and e Velorum -- note that these are lowercase letters in the Latin alphabet, as opposed to either Delta Velorum or D Velorum (these names, like the Unix operating system and the PostScript language, for example, are case sensitive). Interestingly, d Velorum is actually a double star discovered in 1835 (by John Herschel, I wonder, on his famous trip to Cape Town?). At 228 light years, this pair separated from a terrestrial vantage point by about 45" (arc-seconds) are in a rather closer local precinct of the galaxy than e Velorum at about 1436 light years. The base of the triangle, taken from west to east, points toward Trumpler 10 or Tr 10, an open cluster that I might have seen as a "fuzzy star" amid the urban light pollution; it looked to be around the expected distance just to the east of d Velorum, at any rate. Although I did not focus on this at the time, NY Velorum is visually near the eastern border of an open cluster Ruprecht (Ru) 64, which I will resolve to look at more closely next time. However, a glance at the atlas suggests that I migiht be more likely to see some local stars at around sixth magnitude than the more distant members of Ru 64 itself at around 800 parsecs or 2600 light years. In darker skies, things would be different. ------------------------------------------------ 5. The "Alien" Asterism: A majority of variables ------------------------------------------------ Now it was around 0500, and moving further to the east, I focused on Lambda Velorum, now nearing its transit or culmination. Would I find that "alien" asterism that Andrie van der Linde had so appealingly described? The answer quickly proved to be "Yes!" as I happy sketched and refined the pattern of six stars I saw which looked very much like Andrie's, set more or less on its side, or rotated by about 70-80 degrees from the orientation of his sketch in the May 2007 "Sky Log" [or maybe more like 50-60 degrees, since I see on looking more carefully at Andrie's sketch that the pattern is already tilted a little to the left, or counterclockwise]: , * Lambda , , , , Here, as Andrie's sketch shows, the two stars to the west (with Lambda Velorum as the brightest in the asterism) might represent the beginning of the alien's face, with the other four representing a pair of antennae at the top of the head. Describing this difference in orientation to my Mom, I got her very apt response that from Sacramento, the asterism looks like the head of an alien resting on a pillow! Checking the Millennium Atlas, I could quickly confirm and identity the pattern, with names given for four of the six stars, and the unnamed one forming the top of the more southerly "antenna" identified as a variable -- evidently HD80108. Three of the named stars are also variables, with Lambda as type "i" or "irregular," and GX and KL both of type "v" or "other" than the several specific types listed and shown in this atlas. z , * Lambda KL (var-v) (var-i) . , , (var) , GX (var-v) As Andrie says in the Sky Log, this is a wonderful binocular object, fitting very cozily in my 15x70 field. Both to help in locating the alien asterism in Vela, and to give a bit more information, here is some information on the four stars named in the Millennium Atlas, and also the other two, based in good part on a Wikipedia list of stars in this constellation with which the positions for these two stars in the very generously scaled atlas could be readily matched: -------------------------------------------------- Name HD# RA Dec VisMag DistLY -------------------------------------------------- Lambda 78647 09h08m -43o26' 2.23 573 GX 79186 09h11m -44o52' 4.99 ? KL 79416 09h13m -43o37' 5.56 623 z 79735 09h14m -43o14' 5.24 556 -------------------------------------------------- 79694 09h14m -44o09' 5.85 521 80108 09h16m -44o16' 5.12 4025 -------------------------------------------------- Thus with all six stars identified, we have: z , * Lambda KL (var-v) (var-i) . HD79694 , , (var) , GX HD80108 (var-v) An interesting point is that while Lambda Velorum has a notably brighter apparent magnitude (2.23) than the other members of this asterism, its absolute magnitude of -3.99 is not so great as that of the far more distant HD80108 at -5.34, at 4025 light years, with its less visually impressive (from Earth!) apparent magnitude of 5.12 -- actually varying from 5.08 to 5.14. Trying to keep this closer to a "from the scene" observing report than to a dissertation in astrophysics, I'll conclude here by again warmly thanking Andrie van der Linde for a fine description of the alien asterism, and by noting that doing a bit of exploration of the historical and recent literature about the stars or DSO's one sees and the data revealed by investigations at various wavelengths can be an enticing way to appreciate astronomy in more depth. With many thanks, Margo Schulter mschulter@calweb.com "De domo meo NGC 2451 videre possum cum perspicillis geminatis."