Astometric catalog for the F22I field

I've made a catalog of object appropriate for astrometrically calibrating other bands to the F22I.

The criteria are (in SExtractor terms):

MAG_APER < 22.5 
FLAGS == 0

where MAG_APER is measured in a 3 arcsecond diameter aperture.

  • MAG_APER < 22.5 means things are reasonably bright.
  • MAG_AUTO > MAG_APER -1 gets rid of spurious sources on fringes, internal reflections,satellite trails, saturated star spikes and rings. This means hand-drawn masks aren't necessary. Obviously we don't want large patches with no objects (as is the case with masks); the astrometry in those regions would suffer. This condition also ensures (to some degree) that objects  are fairly compact.
  • FLAGS == 0 means no saturated objects, no blended objects, no crowded objects

This catalog is of course useless for scientific purposes.

A visual checks shows no obvious spurious detections and that the coverage is fairly uniform over most of the field. There are of course two small strip were no data was taken; see the the coverage maps at this website. Comparison with the F22B data shows no shifts over 99.5% of the area. Unfortunately, this means that small shifts
do exist in 0.5% of the area. The shifts are of the nature desribed here although smaller in amplitude.

The format of the catalog is:
RA(degrees) Dec(degrees) Mag(3" diameter aperture)

The catalog is found at this site: