iraf.net

Hi all,
I have a basic WCS on my mosaic images which i'm trying to improve with MSCCMATCH. After that i'm reconstructing the images with MSCIMAGE and stack them with MSCSTACK, following this example: http://www.noao.edu/noao/noaodeep/ReductionOpt/frames.html
But the images just don't match after that. At the centers of the ccds are ok, but closer to the edges of every ccd i see multiple stars. I tryed with higher order of fitting polynomial in MSCCMATCH and with different functions but it doesn't improve very much.
When i plot the catalog positions of the stars over the images with DS9 i see that the WCS is improved after MSCCMATCH, but apparently not enough.
Any ideas what may cause the problem?cheers,
bomond

Hi,MSCCMATCH only affects the low order terms of a WCS; namely, the origin, rotation, linear scales, and angle between the axes (skew). To do a full solution you will have to use mscfinder.msctpeak. This is a task based on a package called finder. There is no help page for msctpeak but the interactive help (typing ? when you get the blinking image cursor) is fairly helpful. You might look athttp://iraf.noao.edu/projects/ccdmosaic/astrometry/astrom.htmlFor some information about WCS.Yours,
Frank Valdes