by Matthew Marcus
Many of the regulars were there, but no BBQ. Kind of cold and windy for that, anyway. No matter - Jay brought pizza. Kevin was set up next to me, like last time I was at Dino, and as on that occasion, we left together after everyone else, at about 0230.
From the above description, it may not sound like a very good night, and it wasn't, if what you were interested in was planets or resolution on globs. However, the night was transparent, so lots of good extended objects were visible even with lunar light pollution.
My core list for the night was the article in the Feb. Astronomy (or was it S&T?) about Monoceros and Pyxis. I got every one of the objects on their list except for the Cone Nebula. This is one object which seems to have eluded everyone present.
Here's the list of what I logged:
| 2170/VdB69/VdB68 | Monoceros is chock-full of reflection nebulae, and one area of a few square degrees has something like half a dozen of them. These three look like most RNs - stars with the sort of halo you get from dirty optics or dew. 2170 is the brightest of the three. |
|---|---|
| 2182 | Another, bigger RN in the same general area. |
| 2183/2185 | More RNs, this one a bit more interesting because it connects three stars in an oval of brightness. |
| 2236 | YA RN. This one sits amid a rich star field and is distinctly asymmetric. |
| 2316 | A small, faint RN. Unlike the others, it isn't obviously concentrated at the center. |
| 2260 | OK, not all objects in Mon are RNs. Most of what's listed in NSOG are OCs as this one is. This is a big, loose, oval (E-W) sprinkle. |
| 2452/2453 | A "twofer" in Puppis. 2453 is an OC, mostly unresolved due to seeing, and 2452 is a mag-12, 21"-dia. PN to the S of the OC. Thanks to Peter Natscher for pointing this one out. |
| 2298 | A GC in Pup, mag 9. Unresolved due to seeing. |
| 2245/2247 | Just when you thought it was safe to go back in Monoceros - two more RNs. 2245 is distinctly offset from the star nearest it. 2247 is too, but not as obviously, if only because it's smaller. |
| I446 | An RN in Pup. This one seemed bigger and brighter relative to its star than the ones listed above. |
| I2177 | A very large emission nebula in Mon. This shows up as a bar of light. It goes straight N from its S end (at Cederblad 90) for a couple of degrees, then makes a sharpish bend to the NE for another degree or so. This N part is the brightest. With the 55mm EP and an Ultrablock filter, I was able to follow it all the way up. Remarkably, I could even see it in the Ranger using either an O3 or Ultrablock. Here's a simple calculation which shows how the little Ranger can sometimes keep up eith the C8: The minimum mag on the C8 is 36x (55mm EP), while my minimum for the Ranger is 12x (40mm EP). Now, the surface brightness at the EP is proportional to the square of the aperture divided by the square of the magnification. Thus, since the minimum mag of the Ranger is 1/3 that of the C8, then it follows that the 70mm Ranger delivers the same SB at its minimum mag as the C8 would if its aperture were 3x70=210mm instead of 200mm. Of course, this only applies to extended objects. In and around the nebula are several OCs, of which two are easily detectable - Cr465 and Cr466. I also found the star about which VdB93 is supposed to be, but I couldn't find the actual RN. |
| Cederblad90 | A big RN/EN at the S tip of I2177, just over the border into CMa. It appears 'cut off' on one side, and indeed the photo in NSOG shows a dark nebula 'eating' into it at that side. |
| 2613 | Kevin mentioned a pair of galaxies in the same field in Pyxis for which NSOG got the description backwards as to which one is E of which. This account prompted me to look at them again. I took the oppertunity to make a better sketch of 2613, which is not one a member of that pair, but is in Columba. |
| 2818/2818A | This nice OC/PN combo is the last object in the above-mentioned article. The OC is a neat, round ball of stars, prettily framed in a pentagon of brighter field stars. The PN is at the edge of the OC. |
| 3109 | It was starting to get late enough to bring Hydra into range, letting me clean up a couple of holes in my Deepmap 600 program. 3109 is a very long (20min), low SB galaxy. It was hard to spot without some motion. |
| 3585 | Another Hydra galaxy. This one showed a prominent core and a halo which appeared 'cut off' at the N side as if there were a dark lane there. I have not checked NSOG to see if it's really like that. |
That covers what I logged. I don't log everything, only new stuff or stuff I can record better than I had done before. Here are some objects I didn't log:
With 21 objects logged and 16 more DSOs looked at, it was my most active night in a long time. I've had a stressful work-week, so this extended astro-fix was just what I needed. The Weather Gods be praised for holding off on the clouds for so long in the winter!