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by Jay Reynolds Freeman
I didn't think the momcat would remember me from two months ago, but the little calico approached with the attitude of one expecting to be fed -- and I carry dry cat food in my car for such occasions -- and when I returned from the store with my own meal supplies, she was lying on the threshold of my door. So perhaps we are still friends. I will probably see her again, for the old motel in Colfax is inexpensive and handy to the Sacramento Valley Astronomical Society's Sierra Nevada site, and that location is fast becoming one of my favorite places to observe. It is twice as far from home as Fremont Peak, but twice as high, and a lot farther from the light domes of cities and towns.
I left the motel with hot coffee and fresh bakery cookies, and drove to the location. I started setup just about at sunset. As night fell, temperatures declined to about 20 C, while relative humidity stayed near 35 percent -- not bad for 11 September, nearly a mile up. I had my Celestron 14 ready to go before it was dark enough to see much of anything, so I looked at a few bright globular clusters in twilight, to pass time. Then I began the night's program. I had made a long list of galaxies I had not seen before, that would pass low above the southern horizon, in southeastern Sagittarius, Microscopium, Grus, Pisces Austrinus, and Sculptor. It seemed strange to travel north to view the southern heavens, but the clear sky, high altitude, and absence of light pollution made it sensible to do so.
Microscopium isn't Virgo, but with enough aperture, there are plenty of galaxies to look at anywhere clear of the Milky Way. I skimmed bright ones here long ago, via lists in Burnham's Celestial Handbook, but a dozen charts of Millennium Star Atlas plotted scores more I had not seen, and a handful of Abell clusters, too. I had scanned the Millennium pages centered at 36 degrees south declination, from 20 hours right ascension east to 0 hours. The timing of the observations worked: When I started, 20 hours was just east of the meridian, and I kept up with the Earth's rotation, so the tube stayed pointed straight down the middle of the sky.
It was fun to notice, that most of these galaxies were not in the NGC or IC catalogs. The identifiers that labeled them were generally from the ESO survey. That is not to say that they were particularly difficult; rather, the NGC and IC are sporadic in coverage, and in this part of the sky, lots of galaxies suitable for inclusion were missed. Millennium's selection criteria for galaxies are in fact very uniform. Still, it was fun to think that I was going beyond the usual suspects, even if it wasn't really true. I thought of Doctor Seuss...
In the places I look, there are things that I see,
That I never could name with NG and I C.
I'm telling you this 'cause you're one of my friends:
My catalog starts where your catalog ends!
The trouble with writing a report about this kind of program is that there isn't much to say. I saw a lot of galaxies, but none appeared as more than smudges, showing at most a little shape in the case of spirals viewed obliquely. I doubt anyone is interested in reading a long list of catalog numbers with check marks beside each one, but if I am wrong, send me some EMail and I will type one in.
A few galaxy groups looked like physical associations. The most obvious was a strew of rather more than half a dozen, near bright IC 1459, in northern Grus. (How faint and difficult Burnham's Grus galaxies were, when I first looked at them in the early 1980s! My only previous observation of IC 1459 was with a friend's 16.5-inch Newtonian -- I borrowed a look when I couldn't find things in my C-14. That was from Fremont Peak, though -- the higher elevation certainly makes a difference.) And there were a few other places where groups of two or three or four appeared too closely spaced for just luck, though it is sometimes difficult for the eye to pick out as non-random a distribution that differs but slightly from chance.
The Abell clusters were something else entirely. These are clusters of galaxies. Deep photos of many of them look like wide-angle shots of central Virgo -- and there are thousands of Abell clusters. Looking at them is very humbling, and also very frustrating, for they are all composed of erratically arranged swarms of small blobs, each individually at or below the threshold of my vision with the C-14, perhaps occasionally close enough together to join forces and become more easily detectable in groups.
Millennium's plotted symbols for Abell clusters are deceptively tiny pentagons, but the clusters are often much larger in apparent size -- some are over a degree across. I can't blame the authors for not providing an indication of size, however, for the brightest galaxies are also the most massive, and they tend to sit deep in the gravity well of the cluster, while less massive and fainter members disperse more widely. Larger telescopes will probably show these clusters as larger in size.
What I did was try to take a look at the positions of all of the Abell clusters that Millennium showed on the pages I was surveying. I didn't spend too much time looking for the occasional very wide cluster -- I would just center my 98x eyepiece field on the charted position -- and this atlas has enough stars that those positions were not in doubt, look for a while, and record what I saw. My estimates of angular sizes are rough, made using the known field width of the big Erfle as a yardstick -- they are probably good to plus or minus 15 percent. My galaxy counts are rougher, for the most part -- faint fuzzies are hard to count discretely, particularly when they hover on the edges of visibility, and particularly when there are far more just beyond the limit.
After the fact, I decided to check my observations by downloading images from the Digitized Sky Survey (DSS) for comparison. I had never seen any images of any of these clusters before. I do things like this occasionally, to keep myself honest, and have mentioned the practice here before, but I think this is the first time I have reported it in detail. Of course, it is the same me looking at the DSS stuff, as the me who wrote up the log; possibly I interpret the images to agree with what I thought I saw. Still, at least the images are not plagued with faint-fuzzydom, not at the level of stuff I see through the C-14.
I only downloaded images for clusters that I detected. Here is the complete list, with my logged comments followed by my impressions of the relevant DSS image. The phrase "Did not see" means that I located the plotted position of the cluster but saw no sign of its presence through the eyepiece.
All and all, I am rather pleased with the agreement of visual results with deep images. These clusters were all rather close to the south horizon; perhaps more would have been visible at higher elevations. I will add Millennium's Abell clusters to my observing list as circumstances permit.
At the end of the evening, I chased down a few more showpiece objects, looked at the Sculptor Dwarf Galaxy, and called it a night. I slept very late the next day -- I had paid for two nights at the motel to obtain that privilege. I lazed around the room, writing up my logbook and filling out index cards for the new objects. I finally got dressed in late afternoon, fed the momcat all she could eat of dry cat food and cheese, and drove home.