iraf.net

Hello IRAF!When I rfits an IRAS or an HST fits image I am told something like...
800 x 800 x 4
I believe this is telling me that there are actually 4 image files in one?
For example, for the IRAS images the second image is actually an error map.
How can I display (or otherwise look at) anything other than the top level
image? Simply using "display" does indeed display the image, but how can I
get at the other image planes?Gordon G. Spear
Department of Physics and Astronomy
Sonoma State University

Gordon,
You need to learn about image section notation (for example, you might
look at the CL User's Guide). What you have is a 3d image with 4 planes.
To display successive frames, try: cl> display image[*,*,1] 1
cl> display image[*,*,2] 2
cl> display image[*,*,3] 3
...(if you're using saoimage rather than imtool, just display them one by one
into frame 1, the only one available in saoimage; otherwise if imtool, you
can put up to four frames into the the frame buffer then use the ALT key or
whatever to traverse through them).Currently images up to 7 dimensions can be handled by IRAF. Any task that
expects a 2d image will default to plane 1 if not otherwise instructed as in
the second example above.Steve Rooke (iraf@noao.edu)