Astrophotography at the SCAC Star Party - Bonny Doon Airfield

Mar 2, 2008

Chris Kitting and I converged here for a night whose prime directive was to record the conjunction between Comet Holmes and the California Nebula. I also wanted to test out some options with my 100mm lens on the ST2000XCM. This combo gives blue halos around bright stars and I suspect it has to do with either the far IR leak in the SBIG IR/UV filter, or perhaps a UV leak shortward of the published transmission curve cutoff. I wanted to try adding in series my 49mm UV/Haze filter from my OM-1 setup. Just before closing up, I also tried adding a third filter; Chris' "high altitude UV/Haze" filter which supposedly blocked more of the UV. None did a satisfactory job of fixing the problem. All the images below were shot with the 100mm Zuiko lens and SBIG UV/IR filter plus Hoya UV/Haze filter.

Comet Holmes & The California Nebula. 9x5min dark subtracted, flat fielded in CCDOPS5, stacked in Registax 4. Photoshop CS2/Astronomy Tools: cropped, levels, 'enhance DSO/reduce stars', 2x 'make stars smaller', curves, 'space noise reduction', 'deep space noise reduction', 'local contrast enhance'.


The Jellyfish Nebula and M35. 9x5min stack in Registax 4, after dark subtract and flat fielding. Cropped, and the usual Photoshop CS2 / Astronomy Tools adjustments. Some tilting in the focal plane added to the UV leak problem. And, some warping appeared with the last two frames which had yet a third UV filter stacked on, so the stack isn't perfect. Not a great photo, but it is what it is...