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Sunday, January 22, 2012

Close-up On Rosette Nebula

Near the center of the Rosette Nebula in the constellation Monoceros is an attractive open cluster. My daughter wanted another try at this deep sky object, after her first attempt a few years ago. I think we fared better this time, though still did not collect as many frames as we would have liked.

Nearly 400 frames from our new front driveway in the cul-de-sac. Given the amount of ambient light we had to deal with, I think it would be better to take this shot with a filter. Pushed post-processing on this one and added my own unsharp mask manually at the end.

Having second thoughts about continuing to use the field flattener. Why?! Well, the AT8RC is *supposed* to be largely coma free and the flattener is just another lense reducing transmission of photons in the optical chain. Was the field really that bad before? I don't recall. Maybe the RC scope needs colimation. When the image is finally processed, it is always cropped into my poster template. Wouldn't any aberrations in the outer field be removed? I recall images taken before the flattener were brighter. What about optical curvature? Well, calibrating each image frame with the flat takes care of that. Just need to create a new flat without the field flattener in place. Hmmmmm...haven't I been here before?

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