iraf.net

NUMBER:	508
MODULE:	imshift
SYSTEM:	-V2.12.1
DATE:	Thu Sep 12 17:05:20 MST 2002
FROM:	valdes

BUG:	Using a shift smaller than the precision of a real value
	(~10^-6) causes the image output to actually have a shift of 1
	pixel except at the edges.  This is caused by the fact that while
	the shift is seen as non-zero, one plus the shift is not
	seen as different from 1.  There is no workaround other than
	avoiding using very small shifts.  Note that using such small
	shifts is computationally not significant.

STATUS:	Fixed in the next release by doing computations in double
	precisions when appropriate.