Stacking subs of different exposure lengths and ISO settings

[Pankaj]

Hi all. To bring out detail in a DSO something like M42 which has great variation in brightness, subs of different exposure and ISO settings are stancked. I read in an old thread that subs of different exposure and ISO settings (along with their darks & bias frames) can be loaded in DSS as ''1st group'' and ''2nd group''. 

However, the DSS that I use, has only one category names as ''Main Group'' which is at the bottom of the this screenshot attached.

Please advice how do I stack these images of different settings in DSS

 

[almcl]

Once you put some files (bias frames would be a good choice) in the Main Group, a new tab will become available, 1st Group,  if you put your lights and flats in this group  a further group tab should open.

However, you may find stacking different length and ISO subs altogether doesn't produce a very good result and it may be better to stack the short  subs and long subs separately and then selectively combine them in your image processing software, maybe using layers and an eraser tool.