Hi all, with the comet getting extrememly faint thought I would try ISO 800 instead of 1600 to see if the finer grain would help to reveal the object better. I doubled the exposure time to 8 minutes, and the results were good, with the comet only just showing up on the standard view. The inverted view is clearer, but to get any of it on the standard view shows me it is an improvement even though sky tranparency was only good and not excellent.
Image is a stack of 14x8 minute exposures with Atrograph and astro 40D.
Standard view with labels.
http://i638.photobucket.com/albums/u...y/ae60399d.jpg
inverted view.
http://i638.photobucket.com/albums/u...y/9e54f260.jpg