Public Star Party in Los Gatos

1997 May 16

The San Francisco Bay area internet-based club, The Astronomy Connection, held a first-quarter-Moon in-town public star party at Fisher Middle School, in Los Gatos, California, on Friday, May 16, 1997. This site is about as good as you get for residential area in a major suburb. Clear sky and undeveloped hills to the south contribute to darkness -- at least, when the Moon is not up -- and the seeing can be excellent, as it was on the night in question.

Some 20 telescopes were in evidence, from 18-inch Obsessions down to Prontos. Unusual or of particular interest were a late-model Astro-Physics 180 mm f/9 EDF, a 225-mm Takahashi Schmidt-Cassegrain (Celestron and Meade, are you blushing?), and a Meade 7-inch Maksutov.

Fewer of the public attended than when Comet Hale-Bopp was at its brightest, but those who came were uniformly enthusiastic. Adults and children alike were eager to see and appreciative of the chance to do so.

Many of us got what was likely our last naked-eye view of Comet Hale-Bopp, dim and washed out by the Moon, sinking into northwestern twilight. At 81x, my 90 mm Vixen fluorite refractor showed an asymmetric central condensation and inner tail, but none of the rich detail that telescopes of this size depicted a month or two ago. Larger instruments or greater elevation above the horizon might have revealed more.

The Moon and Mars were popular. The Lunar terminator lay at about 28 or 30 degrees west Selenographic longitude. The complex rille system in Hippalus and Agatharchides showed rich detail. At 202x in the 90 mm, I traced Rima Hesiodus all the way from its namesake crater into the middle of Palus Epidemiarum. The Vixen also showed at least two craterlets in Plato, glimpsed in moments of clear seeing, and an enormous amount of detail on the floor and walls of Copernicus -- about as much detail in the latter crater as Rukl shows, perhaps more. The big Astro-Physics gave an even better view.

The longitude of the central meridian of Mars was about 230 degrees. At 202x, the Vixen showed Syrtis Major peeping around the Arieographic west edge of the planet, with such dark markings as Nilosyrtis and Boreosyrtis better placed, just south of the polar cap, which was still prominent. Mars's apparent diameter has diminished to 10 arc seconds, and the planet is distinctly gibbous, but there is still a lot to see.

Impressed by the good seeing, I decided to show off some double stars. At 202x, Izar (epsilon Bootis) showed as clean a view as I have ever seen of it, wide enough for the steady diffraction ring systems of both components clearly to be distinguished, but close and bright enough to emphasize the pretty color contrast. Porrima (gamma Virginis) and Castor (alpha Geminorum) provided examples of more difficult pairs. Wide albireo (beta Cygni) was a cinch, even just barely risen, and another nice color contrast. p> The double double (epsilon Lyrae) was a little higher up, and provided an interesting study for newcomers of how double-star observing is done: Seeing was such that although epsilon-two (the pair of nearly equal brightness) was easily separated, it took patience to split epsilon-one. Seeing does not come just by opening your eyes.

Jabbah (the Hutt?) (nu Scorpii) was more of the same; the wider, fainter, CD pair was easy, but AB was very demanding. My sources show the AB separation as 0.9 seconds, which ought to be too close for 90 mm, but I and several other observers saw it cleanly split, still at 202x. Perhaps it has widened since the last measurement?

Finally, I tried Antares (alpha Scorpii). My first view showed no separation -- the star was still too low -- but later, at 202x, there was the companion, pea-green by contrast, next to the reddish primary. The owner of the Astro-Physics 180 tried it too, and for once could not outdo my little fluorite -- seeing-cell size that close to the horizon was such that the image in the larger instrument was seriously degraded, while the 90 mm was much less affected.

During the evening, I also tried a couple of deep-sky objects. M13 showed a nice granular sprinkling of star-points at 81x, and M57 revealed its ring.

Most of us started tearing down between 11 PM and midnight, local time. The star party was a considerable success, and no doubt we will do it again, regularly.

Jay Reynolds Freeman; last updated: 1997 June 1