Fremont Peak

1998 Apr 25

The weather in the San Francisco, California, area on April 25, 1998, would have been unpromising for astronomy if we hadn't just come out of an El Nino season. Yet with recent memories of torrential rains and gale-force winds, the hazy, featureless sky of a deep but not quite cloudy marine layer seemed only an inconsequential deterrent to observing, so I packed my Intes 6-inch f/10 Maksutov and headed for Fremont Peak. Many others had made the same decision -- the southwest parking lot was chock full of telescopes, and Coulter row was pretty crowded, as well.

Fremont Peak was above some of the haze, but the sky was not quite free of it. Though transparency was less than perfect, the 97x that I have been using for galaxy-hunting with the Intes was more than enough to reduce background sky glow -- the lights of nearby towns and cities reflecting off the haze -- to manageable proportions. I successfully logged the last 45 objects on my survey of the "big" Herschel list (some 2514 objects). These were all between 11 and 12 hours of right ascension, located roughly from the bowl of the Big Dipper north, and were in an area where it is easy to star-hop -- I don't think I had to use the finder once after I had initially pointed the telescope toward beta Ursae Majoris.

This survey has been fun and challenging. I started last summer, having already observed the bright half of the big Herschel list as part of other programs. The remaining 1280 objects were nearly all galaxies, and were mostly nominal magnitude 12 and fainter, including a few beyond magnitude 15. (Remember that many published visual magnitudes of galaxies are not reliable.) The Intes six-inch was capable of finding all but a few: A small handful were just too faint, and a fair number of others were in areas where there were many galaxies, so many that I needed larger aperture to identify them all well enough to locate the specific ones to log. I tried a variety of magnifications from 47x through 150x for this program, and settled on 97x -- a Meade 15.5 mm Research-Grade Erfle -- as the best all-round single magnification. Occasionally I used other eyepieces -- after all, some of the objects were other things than galaxies. Friends with larger telescopes helped out when objects were beyond the Intes.

But now I need another observing program. Oh, well...

After wrapping up the Herschel survey, I went through the list of double stars in Sissy Haas's article in the April, 1998 issue of _Sky_&_Telescope_. I had looked at many of them before, but did not have my double-star records at hand, so I tried them all. Sextans was descending toward the southwestern horizon, but even so, the Intes had no trouble with any star listed, except gamma Sextans, which I would have expected to be able to elongate in better seeing. But at 214x, it remained only a blur. Incidentally, _Sky_&_Telescope_ seems to have labeled the wrong star as 9 Sextans on their finder chart. The actual target is the next star south of the one marked, on that chart.

After packing up my own equipment, I wandered around socializing. I had a nice view of the central-Virgo Messier galaxies and of most of Markarian's Chain through a 10-inch Dobson. Then I spent a while with a friend who has a late-model Astro-Physics 155 mm f/7 EDF. We looked at a couple of double stars. At 543x, the telescope split zeta Boo nicely, and at the same magnification it blew epsilon Boo wide open. That high a magnification was actually useful on zeta Boo, for a reason that sometimes escapes notice. Zeta is closing pretty fast -- the separation is down to just a bit over 0.8 arc seconds now. The seeing was such that the star could only be perceived as double infrequently -- perhaps for a fraction of a second every ten or fifteen seconds. Zeta is bright enough that there is no temptation to use low magnification to obtain higher-brightness images, and in order to make best use of the fleeting bits of good seeing, high magnification seemed to help. When the seeing settled, the image scale was large enough that it was clear in an instant that the star was split.

Jay Reynolds Freeman; 1998 Apr 26