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Sunday, August 30, 2009

Hazy but happy

The monthly observing session with my astronomy club up in the West Virginia mountains last weekend was a bit of a disappointment due to clouds and haze. Even the night that was mostly clear just didn't live up to the potential of that dark site. Still, a few of us eked out some decent observations.

I'm not sure how I missed it all these years, but one observer mentioned the globular cluster in M7. Well, it's not really in M7 or even along the line of sight, but it is quite close (the small fuzzy spot about halfway to the right edge and slightly above center in the linked image). That's NGC 6453, a 9.9 mag globular about half a degree to the WNW of the center of M7. In the 10-inch, I really couldn't get resolution, but it did appear a bit grainy, giving the distinct impression of being made up of stars and not gas or dust.

I was up there for three nights. The first night there was some clearing, but it was very hazy. So I spent quite a bit of time on Jupiter. I've gotten to the point where on a night of good seeing, I can correctly identify the four Galilean moons based on size and brightness (as can be seen in this animation of Europa occulting Ganymede back in May 2008)- maybe even a hint of color differences. So we watched a partial eclipse involving Io and Ganymede. I was able to push the power up to 312x, which is the maximum with my Baader Hyperion zoom coupled with a 2x barlow, and which is rarely productive in the generally poor seeing in this area of the world. A couple of years ago I made a mask to stop down the aperture from 10 inches to about 3-3/4 inches with an off-axis hole in a piece of foam board laminated with clear contact paper for dew resistance. (Boy, do we need that around here! We had dew of Biblical proportions on the third night.) You see, I really was missing the sharp details of my Tasco 4.5-inch. This really creates a second planetary and double-star scope. Not only is Jupiter dimmed down to a more manageable brightness, but it sharpens up immensely. I just fasten it over the aperture with three Velcro pieces. So I got some good detail on the cloud bands. And there's something just really satisfying to see those moons as little sharply defined balls. Same with Neptune, which was relatively close, a little further to the NE but still in Capricornus.

The same observer also hunted for several of the comets usually visible at any given time. I did have Comet Christensen (C/2006 W3) plugged into my software chart, and it was an easy find in Sagitta. I guess it was about magnitude 8.5. A nice sized fuzzball with a well-defined inner coma. No tail that I could see through the haze, although at that altitude the transparency was a lot better than down low, where the soup pretty much swallowed Sagittarius and Scorpius early in the night along with all those nice Milky Way objects we were hoping to ogle.

The second night was pretty much clouded out, but on the third night I hunted for several faint planetaries, finding a few but also unable to spot some others. I didn't even try for Gyulbudaghian's Nebula (GM1-2 in Cepheus), one of my favorite challenge objects lately, since I haven't definitively spotted it in the 10-inch from that location (or any other) even on very transparent nights. But someday I will see it in the 10. I know it exists since I've seen it in a 30-inch. Speaking of which, one observer had his 30-inch set up nearby, and I didn't even take a peek through it. Is that stupid, or what? But I get so into hopping from one thing to the next that before I know it, it's time to pack it in. I'm sure you know the feeling.

Tuesday, July 21, 2009

A new Jupiter impact and a deep sky pair

It's been a while since I posted, and indeed, I haven't been able to observe much lately, mostly due to the weather. I did get out to the West Virginia mountains this past weekend. On Sunday night, I got a good look at Jupiter in my 10-inch with excellent seeing conditions. I hadn't heard about the impact of an object in the south polar region, and that's not an area of the planet I usually scrutinize for detail. I did notice in passing that both temperate/polar areas were exceptionally bland. In fact, the north temperate belt was only a barely perceptible thin dim line in one area, and the STB was totally invisible. Only fine scale detail was visible in both equatorial belts- no major features.

This time, and the last time I was out in May, I observed a nice pair of deep sky objects in Scutum. How often do you find a globular cluster and a planetary nebula in the same field of view? Yes, I know- Pease 1 in M15, but come on- that's not exactly one that jumps out at you! Try going just 2-1/2 degrees SSE from M11, The Wild Duck Cluster, and you'll find 8.1 mag globular cluster NGC 6712. Just 23-1/2 arcminutes away in position angle 110 is planetary nebula IC 1295. The planetary is a large one at 90 arcseconds, and although Jay McNeil's list has it at 15.0 mag, it's clearly a lot brighter. It's easily visible without a filter in my 10-inch. A narrow band filter shows a little bit of annularity to it. The globular partially resolves in my scope, making this an interesting pair for observation even if they weren't so close to each other. I didn't find many images of this pair on the web, so it would make a nice target for astro-imagers.

If you've got at least an 8-inch scope and are up for a challenge, there is also a very small 14.2 mag planetary only about 5 arcminutes from IC 1295. This is Kohoutek 4-8 (plotted on my software as PLN 25-4.1). It is visible in Chris Schur's image if you click on one of the higher resolution images. Find the little arc of five stars about 1/5 of the way from IC 1295 to NGC 6712. It is the middle star in the arc. Looks like a star, so you can blink it with an O-III filter to be sure. I did not try for it in my 10-inch, though I might next time out as it's pretty bright. You just need to have an image or very detailed chart to guide you to the right one.

Sunday, April 19, 2009

Fun in Ursa Major

I spent some real quality time in Ursa Major last Friday night (April 17). It was one of those nights that we rarely get around here- exceptionally clear with excellent seeing. And it wasn't even that cold! Motored up to the Blue Ridge foothills, arriving around 10 p.m. thinking the Boy Scouts were already camping there, but discovering it was six more members of my astronomy club instead. So we had a great time observing, I being the last to leave as usual, around 2:30 a.m. I was using my usual 10-inch dob reflector.

I started out in Ursa Major to check out 13.5 mag Type II supernova SN 2009dd in NGC 4088. The galaxy is an 11.1 mag spiral with well-defined arms, although well-tilted to our view. It's cataloged as Arp 18 due to a large, somewhat detached piece at the end of NE arm. The supernova is so close to the nucleus that if you didn't know, you'd think it was the nucleus. Here's an image showing how tough it is to tell. And here's an SDSS image of the galaxy without the supernova. Who would've known?

NGC 4088

I was really getting some nice detail on all the objects, not just because the sky was so good, but I had also just cleaned the mirror. The collimation I did indoors with the cheshire eyepiece was spot on and I didn't even need to tweak it. You don't need fancy barlowed laser collimators, my friends. In fact (ascending soapbox) there's a lot of overkill in the equipment department these days. You don't need all the fancy expensive gear that some proponents find so essential. Get back to basics and you'll have a whole lot more fun (descending soapbox).

NGC 4088 did show the supernova well in the 10-inch and in the other larger scopes gathered there. I could make out the detached section of the galaxy in the 10, as well as a lot of subtle mottling and lumpiness in the spiral arms. The supernova appeared just slightly offset to the SW from the exact nucleus, which would have been hard to tell were the seeing less than excellent.

Nearby is galaxy NGC 4085 (12.4 mag). It appeared about 1/4 of the size of 4088 in the scope, thin, with an ENE-WSW orientation. It has a brighter core, not quite stellar, and some clumpiness to the arms. Better in 150x or higher.

Well, I looked around the area in my charting program and saw lots of other galaxies to feast on, and truth be told, I never did really make it out of this area in Ursa Major except for a quick look at Saturn and a late foray into the Virgo Cluster, although I later realized I had in fact strayed into Canes Venatici without knowing it. After all, there are no borders in space, at least none that I've been able to discern.

Next up was NGC 4100 (11.0 mag), a fat, roughly N-S oriented, cigar-shaped spiral with a stellar core and some clumps along both arms. There seemed to be a slightly sharper dropoff in brightness along the eastern edge.

At that point I was getting pretty cocky (or maybe just lazy) and left the barlow in to hop around to nearby galaxies in 104x, wandering over into Canes Venatici. A little over a degree to the NE is NGC 4157 (11.1 mag), another edge-on but thinner and longer than both 4088 and 4100. 4157 was host to its own supernova back in 1937. That one was the first discovered by Fritz Zwicky with his 18-inch Schmidt telescope at Mount Palomar designed specifically to find and study supernovae. Zwicky and Walter Baade had only a few years earlier written some pioneering papers on the existence of supernovae. So this galaxy has its own little place in history.

Move not quite half a degree from NGC 4157 to the NE and you'll find the 13.3 mag galaxy NGC 4187. It appeared round with a nearly stellar core surrounded by a very small brighter glow and a larger dim outer shell.

Some other galaxies I bumped into along the way:

UGC 6992 (14.7 mag): A very soft, smooth and diffuse oval patch with only a very slightly brighter middle. An SDSS image of NGC 6992 (13.5' x 10'):

UGC 6992

NGC 4026 (10.7 mag): Nice big, bright core with thin arms on either side. In this scope and in my 4.5 inch six years ago, I got the sense that this galaxy really should have a thin dark lane running across its length, but alas that's just an illusion. See what you think. It really ought to have one.

After a break, I took a look at Saturn, which is showing a noticeable tilt to the rings, with the gaps visible on either side of the planet's disk now.

Back in Ursa Major again:

M97, the Owl Nebula: The "eyes" were really coming out well tonight. SE eye is darker w/ and w/o the filter. Glimpses of the central star <5% of time at about 250x especially when zooming in and out slightly. Kept sensing a tiny bright knot or star on SW edge, but there's nothing in particular there in any images. Maybe a slight knot or bulge breaking the symmetry of the edge.

M108 - The star that is often mistaken for the core of the galaxy was unmistakably not a part of galaxy because it stood out so sharply. Knots and details in both arms.

UGC 3594 (14.7 mag galaxy) - Picked it up pretty quickly. Best in about 180x. Round patch visible about 70% of time. Something stellar or sharper in there, possibly its core. Here's an Aladin Previewer image:

UGC 3594

UGC 6228 (15 mag) - Couldn't pick it up. I could see a 14.4 mag star nearby but no sign of the galaxy.

NGC 3530 (13.8 mag) - Easy. Compact, bright core, E-W elongation.

NGC 3517 (13.0 mag) - Actually a bit harder than 3530. Brightens toward the center but not as much, and it was hard to get a shape on it. A little larger than 3530, too. I couldn't really discern the little elongated galaxy visible on its northern edge in the linked SDSS image.

Heading toward Beta UMa, NGC 3499 (14.0 mag): Very small w/ stellar core with fuzz around it. Vague hint of thin elongation NW-SE. Linked SDSS Image shows a dust lane roughly in that orientation.

The other six people had all left by this time (1:45).

So it was time to make a dent in the Virgo cluster:

NGC 4608 (11.1 mag) - round, bright, with a not quite stellar core.

NGC 4596 (10.7 mag) - bright center, almost-stellar with extensions to WSW and ENE. These are actually the ends of the bar and I'm not even seeing the rest of the glow beyond that. The bar only extends about halfway out to the edge in the linked SDSS image.

IC 3608 (15.0 mag) - no luck. Would be a nice one if I could see it. This SDSS image is zoomed in to about 5' x 4', making it appear larger than it would in the standard 13.5' x 10' SDSS image on this site to show the fine detail:

IC 3608

NGC 4567-8, the Siamese Twins (11.5 and 11.2 mag)- I can make out two galaxies in 104x easily. Soft glows both. The orientations are clear. 4568 is a little more brightly concentrated. The core is visible in 4567 but 4568 is just brighter in the central oval area.

NGC 4564 (11.2 mag) - Very close to the Siamese Twins. SW-NE elongation with a bright core and dim, stubby arms.

M58 (10.1 mag) - like a larger, brighter version of NGC 4596. Bar in the same orientation (SW-NE). Very slight hints of mottling in the glow.

NGC 4550/4551 (11.6 and 11.9 mag) - 4550 is brighter, more elongated (N-S). They are angled at about 120 degrees to each other, although 4551 is less elongated, just slightly SW-NE. 4550 has an elongated brighter core with a stellar point toward the center; 4551 has a more diffuse core.

M89 (9.8 mag) - A big, bright, round elliptical. Core gets much brighter and drowns out any stellar point that might be in there.

Finished up at 2:24 with the Moon rising in about half an hour. The wind had been picking up in intensity throughout the night. The temperature was in the upper 40s or slightly warmer with no dew, so I could use the mirror fan to improve the seeing.

Just as I was packing up I spotted a nice -5 mag fireball below Saturn in the west- just happened to look up at the right time! A great way to end the night.

Sunday, March 29, 2009

A cold winter finally nears an end

I did finally get out observing again on Friday, March 20 for a few hours up in the Blue Ridge foothills. Although it was clear, the transparency (and seeing) were disappointing and the temperature hovered around freezing with a lower wind chill. But it was nice to brush the cobwebs out of the scope tube and see a few interesting objects. No one else from the club came out despite my post to the mailing list that I was heading out. Observations were made with my 10-inch dob, Baader Hyperion zoom eyepiece with 2x barlow and DGM Narrow Pass Band filter, where applicable. That's my basic setup that works wonderfully for everything I observe. I like to keep it simple.

I had picked out a few objects in Monoceros for the last time I thought I was heading out but didn't, so I started with those.

NGC 2324 is an 8.4 mag open cluster also cataloged as Collinder 125 and Melotte 59. Per Collinder was a Swedish astronomer who also wrote a notable book on the history of marine navigation and who died in 1975. Philibert Jacques Melotte was a British astronomer of Belgian parents. He discovered the little known 50 km wide moon of Jupiter named Pasiphae in 1908 and died the same year I was born- 1961. NGC 2324 is not too far from Delta Monocerotis and pretty close to the Canis Minor border. It wasn't really obvious in the 10-inch at lower power. Though I could resolve most of it at 60x, the handful of brightest stars are around 11th mag and the rest- about 60 or so visible- are dimmer. Rich but faint. It has a ragged oval shape reminiscent of the Crab Nebula. There's a dim little double star of about 12.5 and 13 mag down off the SW edge, outside of the cluster, with a position angle of about 200 or so on the secondary. The cluster got better as I went up in power until about 180x at which point the seeing, which wasn't better than 6/10 at any time, limited the resolution. This is a relatively young, metal-poor, and distant cluster.

Nearby is the 11.6 mag planetary nebula NGC 2346. Or so I thought, anyway. I had never observed this one, and it turns out I left out a "-" sign in the McNeil planetary file, so I had it plotted about 1.5 degrees off. I've corrected the position in the file I have on the Astronomerica site. You can change yours just by adding a "-" before the declination, making sure the columns after it line up by removing a space. Anyway, once I did find it, it was fairly unmistakable as a planetary with an 11.5 mag central star surrounded by a diffuse glow. Nothing like the images that give rise to its nickname the "Hourglass" or the "Butterfly." In fact, the slightly oval-shaped inner glow was all that was visible, oriented NNW-SSE, which is perpendicular to the "wings" or glass bulbs of the hourglass that are visible in images. Still it's a pretty nice one, especially if you take a filter to dim down the central star and get a better look at the glow. You'll need to start at about 150x and go up from there to see any shape to it. There's a 13.5 mag star just off the eastern edge of it, and it appears that the glow on that side has a slightly sharper, straighter drop off. This planetary is somewhat unique in that its central star is actually binary, with the pair of stars locked in a tight 16-day orbit. This situation is probably what caused the butterfly "wings" effect. The planetary is about 2,000 light years away and about 1/3 of a light year across.

I took a brief look at Saturn, but the seeing really didn't favor planetary observing tonight. The rings are a bit thicker than when I observed them last, two months ago, and I could detect a little tilt to them already.

With a cold breeze picking up, I decided to face the other direction, and turned to IC 3568, a 12th mag planetary in Camelopardalis. There's a bright double star nearby, Struve 1694 (32 Cam, WDS 8682), 5.3 and 5.8 mag, which is where I started from. It's a nice wide one, and sometimes included in lists of the best bright doubles in the sky. The separation is about 20" or so and it's like a pair of white eyes peering back from deep space. There's another dimmer double not far from it- Struve 1720, but at 9th mag and with a separation less than 2", I didn't bother with it, given the relatively poor seeing.

Onward to the planetary. This one showed two concentric shells, not well defined, with the dimmer outer shell extending about halfway out to a 14.3 mag star about 50" to the west. I don't usually see much blue in planetaries anymore, but this one had a hint of it when I first caught it in low power. I used the NPB filter to dim down the central star to get a better look at the nebulosity, though it doesn't do a whole lot to bring that out. IC 3568 was discovered by Robert Grant Aitken, his only IC discovery, using the Lick Observatory 12-inch Clark refractor in 1900. The planetary was misclassified as galaxy UGC 7731 in the Uppsala General Catalog, and it shows that designation along with the IC number on my charting software. So don't go looking for the galaxy!

UGC 7410, however, is a real galaxy of 14.2 mag, less than half a degree to the WNW, but I couldn't spot it. Here's an image from the Aladin Previewer that might help you to try to spot it yourself (north up, west to the right, field is 12' wide, bright stars are 9.3 and 9.0 mag):

UGC 7410

So I decided to go for a few galaxies not quite midway between Alpha Draconis and Mizar and Alcor, the "horse and rider" in the handle of the Big Dipper. NGC 5308 is 11.7 mag. It was an easy pickup in 60x, with a stellar core and nice thin arms- clearly a fine edge-on. The linked SDSS image shows it having thicker, fuzzier arms, but in the scope they look quite thin. If you look at the image you'll see a couple of faint galaxies close in, with a guide star near each of them. I tried to locate the galaxies, and although I could make out both guide stars, I couldn't pick up the galaxies. I'll bet a darker sky might give them up.

A brighter neighbor to NGC 5308 is NGC 5322 at 10.1 mag. It's about 49" away to the SSE. This is an elliptical, which normally doesn't excite me much. See if you can pick out the star just south of the nucleus. The nucleus itself appeared not quite stellar to me, although that may have been a result of the soft seeing. In the linked SDSS image the glow is much more extensive than I could see in the scope. It's really interesting to compare your view to images, so you see how much larger these objects really are! For example, the star south of the nucleus is almost lost in the glow of the nucleus in the image, but in my scope it was just inside the galaxy's glow. The stars to the east and west of the nucleus are only about halfway out to the edge of the glow in the image but well outside the glow in my scope. These stars are also nowhere near as prominent in the scope as the star just south of the nucleus.

After a break to warm up in the car, I took a look at Mizar and Alcor. I sometimes forget what a nice system that is- good for showing off in the scope at public star parties because a lot of people are familiar with it only as a naked eye double. NGC 5204 is an 11.3 mag galaxy about 3.5 degrees to the NNE. It's dimmer than I thought it would be, but I could still pick it up easily in low power. It has the look of a dwarf galaxy, with no clearly defined nucleus and a diffuse shape with hints of subtle texture in higher powers. It is, in fact, classified as a "magellanic spiral," halfway between a bright spiral and a dwarf galaxy, a classification introduced by Gerard de Vaucouleurs in his de Vaucouleurs modified Hubble sequence. He was also co-author of the Third Reference Catalog of Bright Galaxies (RC3). NGC 5204 is home to an ultraluminous X-ray source that has been studied with the Chandra X-ray Observatory and the Hubble Space Telescope.

A quick look at M101, which wasn't too great with the transparency having steadily degraded throughout the night, and with Comet Lulin behind a tree at that point, I packed it in around 1:30 a.m.

Tuesday, February 17, 2009

Underwhelmed by Comet Lulin

I may have observed this comet a while back, but if I did it was very dim at the time and I don't remember. I haven't been out observing since my last post, but here's my brother's take on Comet Lulin (C/2007 N3) from the city with his 4.5-inch Orion Skyquest:
Hi Eric, I just got back in from my first and, given my location, possibly only look at Comet Lulin. I must say I am quite underwhelmed, especially with all the fuss there is about it. I had very good sky conditions, though it was still quite low (maybe 20-25 deg.) I can see it being 6th magnitude but it is quite large and I have seen comets at least a magnitude fainter with greater surface brightness. It was not visible in my finder. Naked eye limiting magnitude in that part of the sky was about 4.5 (I could just see nearby Theta Virginis.) Some central condensation but generally a large diffuse fuzzball. Not worth staying up till 4 when it transits, this being a work night!
My brother has also been busy compiling an Unofficial Sky & Telescope NGC/Messier/IC Index to help other packrats find Sky & Telescope articles referencing deep sky objects. Check it out and start getting more use out of all those back issues of S & T your spouse keeps threatening to donate to the local school (or recycling bin)!

Friday, January 23, 2009

Gemini, Monoceros, and a Frosty Leo

Unusually cold weather brought a lot of unusually clear nights recently. But it wasn't until last night that it was finally "warm" enough to meet my own standards (above 20 deg. F) for observing, so it was off to the Blue Ridge foothills. Some passing clouds covered a good part of the sky at times, but curiously my observing was affected very little. I guess I picked the right spots this time. 10-inch f/5 dob. I observed from 9 p.m. to 2 a.m. Transparency variable- 8/10 at best, seeing 8/10 to almost 10/10 at times. Limiting magnitude variable across the sky, about 5.8 at best.

I checked on comet 144P/Kushida again, which is close to the Hyades in Taurus. I had observed this last New Moon. It was bigger and a bit brighter, but otherwise not changed much. The inner core had been stellar last time as I recall, but it was larger and more diffuse this time around. The outer coma extended a good 4 arcminutes in diameter. Eighth magnitude? No tail.

I figured I'd try for 29P/Schwassmann-Wachmann 1, as it was reported to have had some recent outburts. It's in eastern Gemini near the Cancer border. I found it 9 arcminutes off the position plotted by my charting program, but pretty easy to spot as a 13th mag fuzzball about 2 arcminutes in diameter, condensing very slightly at the center. It was faintly visible in 52x but best around 140x. Gave the impression of a cloud of debris. Now if I could only learn to pronounce the name without sounding like I'm spitting out toothpaste - one of the more unfortunate co-discovery pair-ups!

I'm an opportunistic observer, so I turned my attention to a pair of faint galaxies residing far beyond the comet, but in nearly the same line of sight. These are NGC 2480 and NGC 2481, magnitudes 14.3 and 12.7 respectively. 2481 is much more condensed and therefore easier, with a distinct NNE-SSW orientation. 2480 is a whole lot dimmer, and I could just detect its presence very close to the NNW in 312x using close averted vision (looking only about 10% of the field of view away versus the normal 20-80% for me).

Being in a leisurely observing mode, I meandered over toward the Eskimo Nebula, on the way picking up the open cluster NGC 2420. This is an 8.3 mag group of perhaps 30 stars visible in my 10-inch. The diffuse glow of dimmer background stars suggested this contains more stars than I could resolve. The cluster is in something of a twisted diamond shape with a tail of three stars that curl to the south and then west. The closest in of these three stars showed up as a nice double in 250x, with a position angle of about 220. The Hubble Guide Star Catalog identifies the primary as GSC 1373:2235. This is a nice cluster.

If you go from the cluster in PA 070 about 40 arcminutes you'll find Struve 1124, which consists of two 9th magnitude white "eyes" staring back at you with a straight line of three stars right next to it, a curious little asterism. Here's an image from the Aladin Previewer:

Struve 1124

The Eskimo Nebula (NGC 2392) was just great with such good seeing. The central star was nice and sharp and the bright inner circle well differentiated, along with hints of detail in the "parka." The DGM narrow passband filter dims the central star down almost to invisibility, providing a better view of the shells, but I prefer the unfiltered view because the central star is a key element in the attractiveness of this planetary nebula.

Again, being opportunistic (a euphemism for lazy, as you may have guessed by now), I took a short 20 arcminute walk over to 14.5 mag galaxy UGC 3873 from there. This galaxy showed up as a very dim slash, very soft with no central condensation. It took 140x plus just to see it at all. This is another one for which I had to use "close" averted vision, it was so dim. This is definitely one that my eyes wouldn't have picked up just scanning around the area. The linked image is pretty cool, showing the Eskimo Nebula and the dim galaxy off on the side of the frame. Yeah, it doesn't take much to get this old boy excited.

In my Nov. 27, 2008 post, I described looking for and not finding Sharpless 2-188 and compared it to the Medusa Nebula. With that relatively fresh in my mind, I figured to take a gander at the Medusa, Abell 21. This planetary nebula is in southern Gemini, just over the border from Canis Minor. Without a filter I could only get a sense that there was a slight brightening in the proper position. It was much better with the NPB filter on. After studying it for a while, I could begin to make out the crescent shape, the horns and opening pointing toward the NW. 60x was best. Any more and it just faded out. The best strategy on this is to have a nebula filter, dark sky, low power, and good image showing some of the surrounding stars to help you get the right location and orientation, since it is pretty large at about 10 arcminutes across.

Moving 36 arcminutes to the NW as the opportunistic crow flies is a decent open cluster, NGC 2395. Normally I like my clusters dense, not scattered, but this one makes a neat flying bat or pterodactyl shape, so I put it on my list of "worth checking out." Okay, you don't see it? Look for the head to the SW (to the lower right in the linked image), wings to the NW and SE. Hard to see it in an image - you gotta go live. About 35 stars or so. This one also goes by Collinder 144.

Two and a half degrees to the west, as the lazy pterodactyl flies, is open cluster NGC 2355. Now this one fits my dense criterion fine, with about 40 stars visible in a small patch in my 10-inch. There's a tail of stars that trails off to the south. Look 6.5 arcminutes in PA 030 and you'll see a funky little asterism of four stars in a rectangle and a brighter one at one end that reminds me of a turtle with a brightly glowing head (yes, it was getting late and I was a bit loopy by this time). Here's the Turtle from the Aladin Previewer:

Turtle (SAO 96722 and friends)

Swedish astronomer Per Collinder must have spent some time in this area because NGC 2355 is also designated Collinder 133.

At this point I decided to give the rest of the sky a little scope time and moved over to try to spot planetary nebula Kohoutek 2-2 (PK 204+4.1) over in Monoceros, the Unicorn (which also looks like a pterodactyl to me). I had no image to go by at the time, but it's supposed to be 12.5 mag and 415 arcseconds in diameter. However, it must have very low surface brightness- not surprising given its size- and I wasn't able to see it. Here's an SDSS image (13 arcminutes wide) that I haven't yet added to the SDSS pages:

Kohoutek 2-2 (PK 204+4.1)

But as luck would have it, there was an interesting necklace of stars about 45 arcminutes to the SE that contains a Struve double at its eastern end, STF 986. This has a 9th mag primary and a 9.5 secondary at PA 165. I guestimated the separation at about 15 arcseconds, which is well off the cataloged 5.4 arcseconds. This pair is the same as WDS 5572 (Washington Double Star catalog), which lists 54 arcseconds. That seems a bit wide to me. 15" and I'm stickin' to it.

After a break I wandered over to one of my favorite objects, Hubble's Variable Nebula (NGC 2261). The brighter part of this roughly triangular nebula formed a hooked bill shape, or a blunt claw, due to a dark incursion just back of the star R Monocerotis, which gives the nebula its glow. A fairly dramatic fade-off to the NE gives it more of a crescent shape (you thought I was going to say pterodactyl shape, didn't you?). In lower powers the dimmer parts fill in more and it looks more triangular or fan shaped.

I had added the Frosty Leo planetary nebula to my Jay McNeil list of planetaries compiled for The Sky v. 5, but had never observed it. So I headed over to the Big Cat to check it out. This one is relatively bright at 10.5 mag, but it's small, as in starlike, at lower powers, and so a good position and chart is essential. The higher the power, the better to make out its slightly elongated shape. There's a star close to it that helps. The NPB filter dims the nebula about as much as it dims the star, so no real assistance there. Steven Waldee has a nice discourse on this object after he loaded the position into his newer Sky version 6 after much gnashing of teeth and observed it.

Steven remarked that galaxy NGC 2958 was close to Frosty Leo but he neglected to try for it. So I did. He didn't miss much. Just a small spot, nothing more, in 156x.

But not too far away to the NE is an interesting trio of galaxies, NGC 3016, NGC 3020, and NGC 3024. The brightest is 3020 at 12.1 mag, followed by 3016 at 13.2 and 3024 at 13.3. All three fit within a 15 arcminute field of view. The nuclei are all condensed pretty well, but I needed 80x or more to see them well. 3020 and 3024 are more elongated and their orientation is discernible. 3016 is harder to get a handle on. If you're up for a challenge, there's also 15.2 mag NGC 3019 in the middle of the trio, but I can rarely get that deep with the 10. This SDSS image (13.5 arcminutes wide with north up) shows all four galaxies (3020 top, 3024 left, 3019 center, and 3016 lower right):

NGC 3020 group

A quick look at Saturn with three moons off to the west and Titan on the east, and it was time to put away the toys and head home. I left too early to take a look at Comet Lulin. I'll leave that for another night.

Saturday, January 3, 2009

Quadrantid Meteor Shower 2009 report

Last night I finally made it out to the Blue Ridge foothills again, arriving around 11 p.m. when the waxing crescent Moon was just setting. I had intended to observe mostly planetary nebulae, but a friend from the club showed up and after about an hour we noticed enough meteors that we abandoned our telescopes and dedicated the rest of the night to observing the Quadrantid meteor shower.

The Quadrantids are a very steeply peaked shower that aren't observed much because they are only visible from the northern hemisphere at a time that most people aren't willing to sit around outside and freeze. Enter the die hards. We had been prepared to observe anyway, and I've always got my reclining chair in the car "just in case."

Well, I must say, it was quite a show. Although the Quadrantids are generally known as faint and fast, these were fast, but certainly not all faint by any means. We saw quite a few that were first magnitude or brighter, including one at least -5 over toward the eastern horizon. As is often the case in meteor showers, they tended to clump together. Earlier in the watch they often came in pairs, close to each other and parallel, while later we had several flurries where we counted 8-10 within the space of a single minute! Limiting magnitude at this site ranges from about 4 in the east (Washington D.C. metro area) and last night nearly 6.0 in a small area directly overhead because it was so clear. No clouds at all, no haze, and thankfully no dew (which would have been frost, given temperature in the mid to upper 20s (F). The wind made it a bit challenging, but the meteor display made up for that and more.

Although we weren't initially planning a meteor watch and didn't keep official counts with periodic limiting magnitude estimates and all that, I estimate that rates were probably 100 or more per hour from midnight until dawn.

Prior to abandoning the scope, I checked out Comet 144P/Kushida, which is about 10th magnitude (more experienced estimates placing it a little brighter) a few degrees from 5 Tauri. It was an easy pickup, with the round coma extending to a diameter of about 2.5 arcminutes and a dim nearly pinpoint condensation in the center visible in averted vision in my 10-inch f/5. No tail visible.

I tried for planetary nebula PK 174-14.1 which is about 1.5 degrees NW of 95 Tauri. It is 15.3 magnitude and about 20 arcseconds in diameter, but despite a couple of glimmers that I couldn't confirm, it was invisible in this scope and sky combination.

I also tried for IC 2087 (Cederblad 38), which is not quite a degree to the NE of PK 174-14.1. This is a reflection nebula around a young stellar object named Elias 18, which is embedded in a dark cloud of obscuring dust known as the Taurus Molecular Cloud. Once again, despite using a range of powers, I could find nothing in that spot. This one is also tough because there are no guide stars in the immediate vicinity due to the obscuring molecular cloud. Locating it with high power is therefore problematic. Amateur guru Steve Gottlieb described the view in his 17-inch as "a fairly faint direct vision object, moderately large, round, 3'-4' diameter. Fairly well defined although edges fade into background." This is one I could conceivably pick up from a darker site with the 10-inch, and I'll put it on my list, once I get around to making that list!

The two aforementioned objects took up about an hour of observing time, all for naught. So I chose NGC 2371/2372 as the next object. This is one of my favorite planetary nebulas, located in Gemini. In the 10-inch I can see two lobes oriented SW-NE, with the SW lobe the brighter of the two and faint nebulosity connecting them. In the center is a very dim central star, just visible with averted vision with the scope in perfect focus. This is one I've observed with a 30-inch in Arizona, at which time I was also able to see the two puffs of gas about 2-3 times further out than the bright lobes and perpendicularly aligned to them. I call them the "outriggers." But this is a great object in any scope that no observer should pass up. It responds well to O-III and narrowband filters.

Driving home directly into the sun in the morning is not something I would like to do regularly. I don't know how commuters who live way out west of the city do it every day without going blind trying to see whether the numerous traffic lights are red or green. Night is so much nicer, and usually I try to leave before our own star is up over the horizon!

Have a happy New Year! Let's hope for clear skies on moonless nights.