A nice pile of astronomical programs put together by ESO:

  http://www.eso.org/sci/data-processing/software/scisoft/

They don't have a specific RHEL or SL repo, but their FC6 one works well
for me.

-- 
 	    Alec Habig, University of Minnesota Duluth Physics Dept.
	    		    [log in to unmask]
		       http://neutrino.d.umn.edu/~habig/