DSO Novice, Needs Help and Advice Please

[lensman57]

Hi

I have attached two thumbnails of a capture of M13 from last night. 15 subs of 120s, 10 darks, 5 flats, and 5 bias, canon 1000d unmodded,Skywatcher LP filter, Apt for control and DSS to stack and CS2. The scope was SW 100 ED with a 0.85 reducer flatner. I took my time focusing and used the focus aid of Apt. The stars show a dark core as if they are not in focus. One thumnail is the end result and the other ( with colour cast) a crop of one raw capture file . Any help is greatly appreciated.

Regards,

A.G

[Yoddha]

Hi A.G.,

It looks like you have lowered too much the light point in PS. If you are using the "S" shape in Curves, don't lower too much the right side