A little observing 3/30

by Matthew Buynoski


By now mildly desperate for photons (between one thing and another I have not been out in almost 4 months), a couple of the HVAG regulars decided to go up there on a 1st quarter weekend, the new moon having been--again--rained out. We were advised by the ranger to use Halley Hill, as a horde of bicyclists were having a convention or something, and were set up at the normal Telescope Row spot.

So in due course we got there just after sunset and started setting up, my C14 and his 10" dob. We had a pleasant surprise as another photon-deprived HVAG regular popped up, with a 5" ETX.

Conditions were sort of OK. There was a breeze, which actually got stronger later on, so the seeing was at best soft and at times abominable. It was also surprisingly chilly after the warm day. Some thin cirrus were lurking around here and there most of the evening, mostly to the west and northwest but sometimes sneaking in to the northeast with an occasional foray to the east. Transparency was OK. We could not see the dimmest star in the Little Dipper, but further toward the zenith and to the east/southeast, things were about as dark as you might expect with a bright half-moon in the sky. No sign of dew all evening.

We all started off with the quickly visible stuff: Jupiter, Saturn, the Moon. Both major planets were pretty sad, especially Saturn which was down in the "mush". Jupiter did show two major bands and occasionally one or two others. The moon, however, was great. Perhaps it was just the rush of fading photon deprivation, but it seemed really bright and sharp and clear at the 230X the seeing seemed to allow. One very neat item on the moon. One of the craters (I am no Moon expert, but after consulting Rukl, I think it was Argelander) right on the terminator had two sunrise rays across its floor. That is, the floor was in darkness except for two somewhat cone-shaped streaks of light, one in the northern half of the crater, one in the southern, dividing the crater floor into three roughly equal dark areas. We all ogled this, and later on in the evening, the 5" ETX came back to it, and you could clearly see that the view had changed slightly as the sunrise progressed. Neat!

Of course, we looked at the Orion nebula, which was mainly washed out by the nearby Moon, but still (for the photon deprived) a great sight. Occasionally, the E star of the trapezium could be seen winking in and out in the C14 as the seeing bounced around.

Some viewers arrived, mostly 3 of the park rangers and the fiancee of one of them. We of course made them look at everything. They enjoyed it, and the session turned into a mini-star-party.

Went on to spectra, another item that can be done sucessfully in a bright sky. First Rigel, and the H-beta line was visible, and sometimes the H-gamma. H-alpha and H-delta were not showing, too unsteady. Went on the Betelgeuse...wow! Molecular bands were showing very clearly: two in the red, maybe one in the orange, two thin ones in the green, and two or three in the blue (the last probably from TiO or ZrO, from comparing with the spectrum in Kaler's book). Sirius was A type all the way, with H beta showing easily, and maybe gamma and delta; no alpha.

The rangers had seen the aurora last night, and we were all hoping for a repeat tonight. Two of the group thought they saw some pinkishness to the sky in Draco below the Little Dipper to slightly east (in the Earth sense) of that. If so, it was very, very subtle and went away fairly early.

Tried a few galaxies in Leo. Even the "best and the brightest" (M51, M65, M66) were pretty washed out, no surprise with the Moon up.

So I laid back on one of the Halley Hill benches, watched the sky wheel overhead, kept looking for aurora (no luck), BS'ed a lot, swapped stories, and did a little discussion of equipment. We left early, around 11PM, but thoroughly glad we'd come.