NUMBER: 332
MODULE: apphot.daofind, daophot.daofindSYSTEM: V2.10
DATE: Mon Mar 18 09:06:06 MST 1996
FROM: davis
BUG: The is a bug in the daofind centering code which results in incorrect
fractional pixel corrections being computed for the detected objects.
This error can most easily be detected by plotting the histogram of
the fractional pixel corrections for an image with a large number
of detected objects. The histogram will be modulated at around the
20% level with 'peaks' around the 0.33 and 0.66 fractional pixel
values.
This bug is also present in the standalone version of daophot ii.
Users concerned about this bug should obtain a fix from Peter
Stetson.
STATUS: This bug is fixed for the next release of iraf and in the external
addon package digiphotx version of daofind. There is no workaround
although it should be emphasized that this bug does not affect
the centers computed by the psf fitting code in the peak, nstar,
and allstar tasks. Users concerned with precision in the find
step should upgrade their software, or recenter the objects with
the phot 'centroid' (fast) or 'gauss' (more precise) routines.