iraf.net

I just now noted something about imcopy. I have long image strips fro a drift scan. I use imcopy to slice them into smaller images. The header doesn't have a lot of usable info in it. However, when I do a single copy, such as
imcopy input[1:3000,*] output, I get all sorts of stuff in the output header that is not in the original, including a CD matrix. Where does this come from?
Jim

IMCOPY of a section adds the keywords to tie the new image back to the parent image. This is automatic in the task but you can use WCSRESET to reset the physical wcs of the new image (i.e. remove the offsets if wcs=physical, or remove the world coords if wcs=world).