If you have detailed questions about the program, its theory or implementation or basic use, I suggest you visit the Yahoo group IRIS_software and ask your questions there.
I may add illustrative pictures to this tutorial some day. But until that happens, please refer to my Rosette Nebula (NGC2237) image, processed using this technique.
Start with the 4 FITS files in the same folder
load LThis loads your L frame on the screen. This step is not vital, but makes sure you are on the right track. Next, type
coregister L RThis registers the R frame to the L frame, and puts the registered R frame on the screen. Next, type
save i1This saves the aligned red to a file called "i1.fit". Now register G and B against L.
coregister L G save i2 coregister L B save i3You now have 3 aligned fits files i1=red, i2=green, i3 = blue... they are aligned to the L.fit. Let us go further and scale the colour ... load the red one with...
load i1Using the mouse, draw a square around a non saturated sun-like star... well repeat the scaling command with different stars until you like the balance... and type
scalecolor i j 1 3This scales the i1,i2,i3 to balance the colours and save it to j1.fit , j2.fit , j3.fit ..... the third parameter is the reference frame and the fourth is the number of frames. Next make the colour picture from the registered R, G and B frames
trichro j1 j2 j3You now have a colour picture on the screen. I may not be perfect at this point, but save this as TIFF, colour FIT or, what i do, save it in photshop PSD format
savepsd colourwhich makes a colour.psd.
Open this in photoshop or whatever program you have available. Adjust the curves as normal. Tweak the colour balance. Then... if you are in photoshop, you can open L.fit and copy paste it on top of the colour picture while blending luminosity. To make it even better, you can also consider using Robert Gendlers Multiple Luminance Layering (LLRGB) technique.