There are two ways to interact with this program, either through
the GUI interface, or by the commandline using the program's object
reference. In the first method, you can call up the program and
pass various arguments. For example, to load an image from file and
zoom in on a particular region, you might type:
IDL>
plot_fits, 'file1.fits', limits = [40.5, 40.8, -0.3,
0]
A full listing of these arguments is outlined here.
In the second method, you would load the program like so:
IDL> plot_fits, obj = obj, /nogui
You would then proceed to call object methods, which are like little
routines. In IDL, object methods are called using the "->"
operator. For example, if the object reference is "obj", we could
load an image like this:
IDL> obj->Load, 'file1.fits'
Then we could zoom in as before like this:
IDL> obj->Limits, 40.5, 40.8, -0.3, 0
There are many object methods, and they are all listed here.