Download the package here: astronomical PAN (tar file, 1.35 Mb)
To install, untar the package and add the path to your IDL !PATH in the .idlrc file.
If you don't have an .idlrc file, then you should create one in your home directory and add the following lines
!PATH = expand_path('<IDL_DEFAULT>' + ':' + '+/path/to/your/pan/directory') device,true_color=24 device,decomposed=0 device,retain=2 ;set colours 0 to 7 to be black, red, green, blue, cyan, ;magenta, yellow and white, in that order. red= [0,1,0,0,0,1,1,1]*255 green=[0,0,1,0,1,0,1,1]*255 blue= [0,0,0,1,1,1,0,1]*255 tvlct,red,green,blue
On the idl command prompt, type 'pan' to begin.
Also, make sure you've got the IDL AstroLib files installed.