Comet K4 LINEAR; Photography at Cabrillo Observatory - Aug 2, 2004

Sharahm and I met before dark and got his 10" f/4 Meade LX55 Schmidt-Newtonian with focal reducer (to f/2.5) set up along with his 500mm f/8 refractor piggy backed. I'd planned on using the GM8 and STV autoguider, but I forgot the STV manual at home and so just polar aligned the GM8 and let Shahram use it for film photography while I worked at the 12" in the dome. The scene above shows the 92% waning moon rising above Hort Hill, the 10" on the right, Shahram lost in the shadows, and me on the left of Shahram's laptop LCD, on which the ToUcam is integrating 1-minute pictures of the comet.







I'd just bought a Meade f/3.3 focal reducer to replace our f/6.3 reducer. I'd hoped to get smaller star images and a wider field of view. I took this 5-minute self-guided shot at 9:50pm through the 12" LX200 with f/3.3 focal reducer. The comet was about 35 degrees up and the moon was still below the eastern horizon, just barely. I'm disappointed at the coma still evident in the stars. It may have to do with excessive slack in the gears and a poor guiding calibration with the f/3.3 reducer, so I'm going to play with it some more before a final decision. Still, the gas tail pointing straight back is clear, as is a second, curved tail. vignetting is obvious, but will require taking some flat fields to fix. The problem I believe is that the backfocus is wrong.







Sharahm got this nice color picture after stacking ~30 ToUCam pictures of 30 - 60 second duration, taken through his 500mm f/8 refractor. The source of the color gradient isn't clear - there's some post-processing work clearly to be done.