Are you sure this is an image and not an event list?
If it is an event list, saoimage can't handle it.
You'll have to make an image using dmcopy
dmcopy "acis.fits[bin sky=8" img.fits
or use ximtool (saotng) within IRAF, which I think (not sure)
*might* be able to handle event lists.
This archive was generated by hypermail 2b29 : Mon Dec 09 2013 - 01:00:03 EST