by Jay Reynolds Freeman
On Friday, 10 December, 1999, I drove to Mariposa, California, to spend a couple of nights observing at the private observatory of a friend, nearby in the Sierra Nevada foothills. I had with me both Harvey, my white Celestron 14, and a new 3-inch f/10 Newtonian from Stargazer Steve. I have already reported separately on the little 3-inch, which I used exclusively on Friday evening, between passages of clouds. On Saturday, much better weather prompted me to set up my C-14.
A thin crescent Moon lingered in the western sky as I accomplished the final tweaks to Harvey. It wasn't very bright, so I anticipated being able to conduct faint-object deep-sky observation at magnifications higher than rich-field. Yet on trying 244x (Brandon 16 mm) on Jupiter and Saturn, I found the seeing disappointingly poor; thus I was reluctant to spend much time on faint fuzzies at that magnification. So I put in my 98x eyepiece (40 mm Vernonscope Erfle) and just loafed for a while, looking at showpiece Messier objects that have plenty of grandeur for such circumstances. Presently I had worked my way across the sky to Orion, and after a magnificent view of the Orion Nebula, I decided to review some of the interesting non-Messier objects in that part of the sky.
Though M42 and M43 collectively comprise the brightest gleam in the sword of Orion, there are other deep-sky objects associated with that blade. Nebula NGC 1980 wafts thinly in the vicinity of its southerly star, and a coarse handful of background stars in the vicinity comprise cluster NGC 1981. The cluster was easy but the nebula a bit harder for Harvey. Nebulosity also swirls in the vicinity of the sword's northern star; the three brightest patches of a large nebulous complex have different NGC numbers, 1973, 1975, and 1977. They are very different in size, but I could see all three of these patches at 98x.
I moved the telescope eastward, past sigma Orionis -- a pretty multiple star that warrants scrutiny with higher magnification when the seeing is better -- to the vicinity of zeta Orionis, where many other bits of nebulosity abound. The brightest and most extensive of these is NGC 2024, a broad patch north and east of zeta. Perhaps the most common name for it is "The Flame Nebula", but I prefer the title "The Tank Tracks", for in the 98x eyepiece it indeed resembled a patch of glowing mud or puddle across which are two wide, irregular, curving tread marks.
South and east of zeta is a 7th or so magnitude star with a blob of nebulosity around it; this is NGC 2023. I often double-check the detection of circumstellar nebulosity by looking at another star of similar brightness, to be sure that what is seen is not merely scattering in atmosphere, telescope optics, or eye, but in the case of NGC 2023, I must take special care: The next comparable star east also has a blob of nebulosity around it, IC 435. I could see that one, and also IC 432 north of Zeta. IC 431 is smaller than IC 432, and near it, and IC 434 with its famous superimposed dark nebula, B33 -- the Horsehead Nebula -- trails off south of zeta. I did see the latter three objects on the night of the 11th, but not until later, after the Moon had set.
Temperatures most of that evening hovered near zero C, and the relative humidity was at about 85 percent, yet my Kendrick anti-dew heater kept Harvey's corrector plate clear of dew and frost, and disposable catalytic heaters in my gloves and down booties kept me from being bothered too much by the cold. The observatory owner had a Franklin stove in the small cabin on the premises, and kept it all fired up, too; from time to time we retired there briefly to warm up.
As Luna settled, I switched to fainter objects. Two clumps of half a dozen or so galaxies each lie between NGC 891 and M34. The first, nearer NGC 891, encompasses NGC 906 and several others; the second, almost all the way to M34, involves NGC 1000. The C-14 showed all the galaxies plotted in Millennium Star Atlas in these clumps, and more besides. Then I looked at random galaxies selected from those plotted in Millennium in Fornax and in Eridanus, and some Abell clusters of galaxies in that area as well. The plotted Abell clusters are often beyond what I can see with Harvey, but I did spot several, either as fluffy patches of unresolved galaxies or as groups of a few very faint individuals.
Despite the high humidity, the Sierra foothill sky was unusually transparent. After the last of the moonlight had gone I had a quite solid naked-eye sighting of M33.
The winter Milky Way has a lot of loose, bright galactic clusters that were overlooked by the compilers of the NGC and IC simply because they were too broad and too bright. Many of these are plotted in Millennium and listed in Sky Catalog 2000.0. I have lots on my "cats and dogs" list of objects to observe, and spent a while on that evening going through a dozen or two. Many of these clusters are far broader than the widest field of view I can get with Harvey; I end up logging them as "several rich fields", or some such. The whole belt region of Orion is one such cluster, Collinder 70, and many other clusters in Collinder's catalog are there as well, for the most part bright, sparse and easy, or at least the ones in Sky Catalog 2000.0 are.
I took down my equipment and headed back to my motel room by about midnight, after perhaps four or five hours observing. It had been a very good night.