ds9_rwcs

Very old code: This script was prepared early in 2015 when I was still writing fairly large, monolithic scripts. In other words, a single script would handle ds9 image display, region reading/writing, etc... Now (July 2016) I would use a script like wcs_refine to do this sort of thing. Some parts of ds9_rwcs may remain useful, so I retain the source code.

View an image that has an initial WCS solution already installed (such as that derived with the wcs_getA script). A collection of catalog stars from a cdfp file (usually from STARS.cdfp) are overplotted, and a new set of X,Y,Ra,Dec data sets are established. 

 

ds9_rwcs A.fits STARS.cdfp 

arg1 - names of fits image to be revised
arg2 - name of cdfp file
There are basically two ways this routine functions:
  1. All possible "matched" stars are used for the revised data set.
  2. Only stars that the user has "CHANGED POSITIONS" for are used for the revised data set.
By far, the first mode is the one used most frequently, but this will only work for the case where the initial WCS solution was pretty good. If a significant image rotation exists, then this approach will often fail. After the user has completed the viewing of the overplotted sources, the returned region file(s) are processed by the OTW script named wcs_r_setup to create a revised "wcs_setup.out" file (the basic list of X,Y,Ra,Dec along with target names used by the WCS solution fitting tasks).



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