Combining Two Night's Data?

Hi All,
I plan to add more data tonight for an M100 I shot the other day--just feel I need more on my lum. Question: how should I add the data? (I use AstroArt3.) In other words, if I align the two different nights separately to create two different masters, then combine those two masters together, is it the same as if I did one big stack of the individual frames? The former would be my choice since it makes aligning much easier (I'm shooting 30 second unguided, so it's a lot of subimages!) Also, if I were to make two masters, would adding be preferable to averaging the two together? Or is averaging okay, too?
Thanks in advance for any advice,
Larry

Larry Durst said:

Hi All,
I plan to add more data tonight for an M100 I shot the other day--just feel I need more on my lum. Question: how should I add the data? (I use AstroArt3.) In other words, if I align the two different nights separately to create two different masters, then combine those two masters together, is it the same as if I did one big stack of the individual frames? The former would be my choice since it makes aligning much easier (I'm shooting 30 second unguided, so it's a lot of subimages!) Also, if I were to make two masters, would adding be preferable to averaging the two together? Or is averaging okay, too?
Thanks in advance for any advice,
Larry

I am not sure how AstroArt combines, but adding all the subs using a statistical-combine method like the Sigma-Reject or SD Mask method will result in lower total noise.

Have fun!

Jeff