Easier way to make RGB images.
January 25th, 2005 by admin
I described in a post last year how to use various IRAF tasks to export nice grayscale gifs of IRAF images and then combine them using various other programs to make a nice RGB image of, in this case, the crab nebula.
However, Laura Chomiuk, over at the University of Wisconsin, pointed out to be that ds9 3.0 and later can created new RGB frames. You can load a different fits image into the R, G, and B frame and then twiddle with the brightness contrast in each frame, and use DS9′s “scale parameters” to adjust the effective z1 and z2 values. It might be worthing displaying the images in iraf and experimenting to find the best z1 and z2 values before going to ds9, because in ds9 it adds the color tint and that can be a bit distracting.
Anyway, it’s certainly another, less complex, method and worth trying. You will have to get ds9 3.0, which of course I still lack an installer for, however. I am, however, uploading new TABLEs and STSDAS installers at this very moment.
Here’s the ds9 combined image below (converted to JPEG in Graphicconverter, I had ds9 export a tiff.)
Image is Missing since the server switchover…. I’ll try to track it down.
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