combine output questions: how to avoid trimming and how to normalize by # of overlapping frames about ccdproc HOT 1 OPEN

Thanks for the questions @gcecill! The short answer to the first question, I think, is that there is no built-in way to reproject the images on the fly and combine them.

We do have this for breaking that into two steps, reprojecting and then combing: https://ccdproc.readthedocs.io/en/latest/image_combination.html#combination-with-image-transformation-and-alignment

The code at that snippet is inefficient in that it keeps all of the reprojected images in memory, which might not be possible depending on how many you are combining. This notebook for a class I teach does the reprojecting and saves to disk, and the saved images are combined in this notebook.

To get the number of pixels in each region, I would look at this from reproject: https://reproject.readthedocs.io/en/stable/mosaicking.html

Should we add something about this to the ccdproc documentation?

from ccdproc.