I posted a link to an image I did last night of M53. When I took a close look at the stars I could see the alignment was off as they just didn't look right. I tried every registration routine available in Maxim and they all looked bad. Then I did a star registration in PixInsight and the stars looked perfect but when I stacked the subs I could see some small black artifacts throughout the image. I eliminated my calibration files and the problem went away. Has anyone ever had a problem like this? I'd love to resolve it. Meantime, here's a link to the finished image: Thanks for looking, Albert http://www.flickr.com/photos/49526053@N04/8641745394/in/photostream/ -- See message header for info on list archives or unsubscribing, and please send personal replies to the author, not the list.