Dear bs3w6, Are you calling the routine like this?: a=readfits('imageName.fits', hd, /EXTEN, /silent) Did you try the example at the end of the page here: http://www.exelisvis.com/docs/readfit... Have you try instead giving a value to EXTEN: a=readfits('imageName.fits', hd, EXTEN=1, /silent) Just to remind you that this are third party routines, that they don't come with the IDL package. I hope that helps. Cheers. Fernando