Dave Wallace's Adventures in Astronomy

04/07/2004 2300 UTC

I got set up at the ATMOB site at about 7:15 local time. By 7:45 it was dark enough to spot Polaris (I thought -- see below), so I did a polar alignment. Things were off by quite a bit, but the Autostar accepted the alignment. Tried a slew to Venus and had to correct by several degrees. Venus is showing a thick crescent (waning) and is very bright -- the image in the eyepiece casts a shadow.

I finally got a chance to star-test focusing with the Hartmann mask. It works good, but because it blocks a significant amount of light, you have to have a first-magnitude star (or a planet) to work with. (I was using Sirius. You can't find a brighter star than that.)

I went to Jupiter next. Off a lot. When I finally got it in view, only two moons could be seen. (They were Io, just finishing a transit of the planet and Callisto. Europa and Ganymede were behind the planet.) The GRS was not visible at that time.

I tried another target and the GOTO was really awful. I was becoming suspicious about the alignment. So I turned around and looked at the northern sky. Sure enough -- I was aligned on Kocab (beta Ursa Minor) instead of Polaris. That put me about four degrees low and almost 20 degrees east of where I should have been. (I need to remember that the observing field is oriented exactly north-south!)

I repositioned the tripod and did another polar alignment. Things were better but still not great. Hit M45 after a bit of work and caught M42 before Orion set behind the trees. Tried to split the close double component of Capella, but no luck. Seeing wasn't great and that's right at (or maybe beyond) the diffraction limit of my scope.

I finished up with Saturn. Titan was easy to pick out but I didn't spot any of the other moons this time. Called it quits at 9:30. While breaking down, I discovered another source of goto error -- the mount was not properly attached to the wedge. I'd not gotten it completely seated. That would have put the RA axis a bit off of perpendicular and the whole thing was rotated a few degrees. I'll have to watch out for that in the future.