iraf.net

NUMBER:	180
MODULE:	identify/reidentify
SYSTEM:	V2.10.1
DATE:	Wed Sep 16 16:24:05 MST 1992
FROM:	valdes

BUG:	If a spectrum is shifted using IMSHIFT with a positive shift
	then the physical pixel coordinates are incorrectly computed.
	The workaround is to reset the WCS with WCSRESET.

STATUS:	Fixed in V2.10.2.

NUMBER:	239
MODULE:	onedspec tasks
SYSTEM:	V2.10 - V2.10.2
DATE:	Sat Mar  5 16:05:55 MST 1994
FROM:	valdes

BUG:    Applying IMSHIFT with a positive shift can cause errors in
	the ONEDSPEC tasks.  Negative shifts do not cause a problem.  The
	same problem has been noted previous in bug log number 180 for
	IDENTIFY and REIDENTIFY.  Errors occur when a wavelength is
	transformed to a pixel coordinate.  This happens in a number of
	operations in SPLOT.  There are various workarounds depending on
	what is desired.  A WCSRESET of the physical coordinate system can
	be used though this will cause the dispersion coordinates to also
	shift; i.e. then the shift will move the pixel relative to the
	image data array and the wavelength coordinate system.  As a
	general rule use of IMSHIFT with spectra, particularly dispersion
	calibrated spectra, should be avoided.

STATUS:	The problems have been fixed for V2.11.

NUMBER:	483
MODULE:	immatch.psfmatch
SYSTEM:	V2.11
DATE:	Wed May 16 14:46:37 MST 2001
FROM:	davis

BUG:	There is a symmetry problem in the convolution step if the psf
	matching kernel does not have 180 degree rotational symmetry, due
	to the fact that convolution kernel is not being flipped properly 
	before doing the convolution. The workaround is to create the
	psf matching kernel, rotate it 180 degrees, and then apply it
	with psfmatch or use the psfmatching kernel directly with 
	fconvolve.

	A floating point error may occur in the replace algorithm in
	rare cases due to the input to the log function not being checked
	for 0.0 values. The only workaround is to try the filter options
	'none' or 'model'.


STATUS:	Fixed for the next release of iraf. A fixed version of psfmatch
	is available in the external addon package immatchx.