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Hello.This might be not a IRAF specific question, but I thought of asking anyway ( maybe it can be done through iraf ).I have many fits images, from the same patch of the sky, obtained with the same instrument. The astrometry has been done on them. I need to construct a mosaic out of them ( I just temporarily need to see the big picture ). I though of loading the images in ds9 as mosaic segment will do the trick but it this does not seem to work..I've tried with ds9 from the terminal, both
"ds9 -mosaic [wcs] *.fits"
and
"ds9 -smosaic [wcs] *.fits"Both do not seem to work, and I get different results ( don't really understand the difference between the two tasks ].So my question is, is there any quick & dirty way of creating a mosaic? It does not seem to be perfect, close enough will do. Which iraf tast should I explore for this?Thanks in advance!

See the IMCOMBINE task (w/ parameter offsets=wcs) and help page.

so ds9 is not able to display the images simutaneously in one frame, and we have to sew them up using imcombine first, right?

DS9 is supposed to do this, and I know it has in the past. If the '-mosaic' and/or '-smosaic' flags aren't working, then try the options under the File load menu. If there are problems or bug reports you should contact SAO.

I checked here
http://stsdas.stsci.edu/cgi-bin/gethelp.cgi?imcombine, but failed to sew images up.

Could you please show me how to write it?

The basic command is of the form



where the WCS in each image will be used to align the images in the output. The result is a single 2-D image you can simply DISPLAY.

DS9 can (or is supposed to be able to) do the same thing using images from extensions of an MEF or multiple images using either the WCS or the CCD geometry keywords. Do your images actually have WCS and CCDSEC/DETSEC keywords in the headers? Is it a WCS that IRAF understands?