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2005.01.06 Comet Machholz was scheduled to make its closest approach to the Pleiades on January 7th, and there was a star party that night in Taos. However, the weather forecast for Toas and Los Alamos indicated snow that night. It was clear tonight, though, and the comet was already within 3° of the cluster, so Bob and I hauled out the LX200 and set it up in his back yard. I had to do a new focus test on the 100mm lens with my new high-resolution marking stickers on the side of the lens. This got us to pretty good focus quickly. I had made a Hartmann mask out of two 58mm UV filters with a piece of paper sandwiched between. It worked great. Though there were basically no clouds in the sky, there was a light haze layer and the fact that we were shooting in town made the fog limit pretty short. We were not able to get any detail in the tails of the comets without going to ISO 800 and/or stopping the lens all the way down to f/2.8. The open aperture led to really badly-shaped stars in M45, so we stuck with the IS0 800 and f/4. Here is the best shot we got on the night: I'm pretty happy with it, but I wish I could have done longer exposures with a slightly lower ISO. The grain is really distracting and the comet tails are hardly visible. |