Stacking - Image Size

[Gr4h4m]

I have a question with regards to stacking images.

Coming from a landscape photography background I’m used to, when stacking, seeing the image size/file size increasing with the more images I stack together.

I’ve just finished processing my first deep sky image using Deep Sky Stacker to stack my exposures, however, the resulting file size is still relatively small, even with 17 hours of exposures.

Am I doing something wrong or is there a setting in DSS I need to change to help with increasing the output size of the resulting image?

[Atmos]

Nope! That’s entirely normal. Stacking in astronomy doesn’t really change the image size because the image still has the same number of pixels.
Where the size will change is going from a 12-14 bit raw file (NEF of CR2 with Nikon/ Canon) to a 16/32 bit FITS or TIF.

What stacking does is average out each pixels brightness so get it closer to its true value but as the number of pixels doesn’t change, the image size doesn’t either.