We need to revise the WCS information in the header so that we can then do geometrical transformations to a a uniform plate scale.

MSCRED uses GEOMAP to do do the coordiante fitting. The "new" version of GEOMAP, in "immatchx", contains a very useful parameter maxiter, which allows the routine to reject outlying points. To take advantage of this, you must do the following:

unload mscred

load immatchx <---immatch for V4.8

epar geomap to make sure that "maxiter=3" (say)

load mscred

Proceed as folllows....We assume here that we will get a new list of coordinates for each frame via the magical call to mscgetcat specified under "coords":

PACKAGE = mscred

   TASK = msccmatch



input   =           obj*p.fits  List of input mosaic exposures
coords  =      !mscgetcat $I $C Coordinate file (ra/dec)
(outcoor=                     ) List of updated coordinate files
(usebpm =                  yes) Use bad pixel mask?
(nsearch=                   60) Maximum number of positions to use in search
(search =                  30.) Translation search radius (arcsec)
(rsearch=                  0.2) Rotation search radius (deg)
(nfit   =                   50) Min for fit (>0) or max not found (<=0)
(rms    =                  0.5) Maximum fit RMS to accept (arcsec)
(maxshif=                   5.) Maximum centering shift (arcsec)
(fitgeom=              general) Fitting geometry
(reject =                   3.) Fitting rejection limit (sigma)
(update =                  yes) Update coordinate systems?
(interac=                  yes) Interactive?
(fit    =                  yes) Interactive fitting?
(verbose=                  yes) Verbose?
(listcoo=                   no) List centered coordinates in verbose mode?
(graphic=             stdgraph) Graphics device
(cursor =                     ) Graphics cursor
accept  =                  yes  Accept solution?
(mode   =                    q)