iraf.net

NUMBER:	332
MODULE:	apphot.daofind, daophot.daofind
SYSTEM:	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.