David Nakamoto wrote:
Because Registax in particular, and astronomy imaging in general, does an
alignment procedure because telescopes do not exactly and perfectly track an
object, due to several factors. So unless the individual frames are aligned
before stacking, you wind up with a blurred planet.

For what you want to do, just use the arithmetic feature on Photoshop or Paint
Shop Pro and add the images one at a time, or in batch mode (although I've not
tried the latter). Registax was designed for a specific case, astronomical
imaging. For that, Photoshop or Paint Shop Pro would be the hard way to do it,
when you're stacking hundreds or thousands of images.


Thanks for the explanation David.

Many thanks,
Steve