iraf.net

NUMBER:	254
MODULE:	longslit.transform
SYSTEM:	V2.10-V2.10.2
DATE:	Sat Aug  6 12:14:32 MST 1994
FROM:	valdes

BUG:	If DISPAXIS=2 and one specifies log sampling (ylog=yes)
	then the specified sampling is done correctly but the header
	coordinate description is incorrect.  Specifically the starting
	wavelength, CRVAL2, is given as a linear wavelength rather
	than a log wavelength.  Display of this spectrum, say with
	SPLOT, produces a wavelength scale which is very compressed
	at the starting wavelength.  The workaround is to fix the header
	of the transformed image with

	    cl> hedit  crval2 '(log10(crval2))' update+

STATUS:	Fixed in versions after V2.10.2

NUMBER:	254
MODULE:	longslit.transform
SYSTEM:	V2.10-V2.10.2
DATE:	Sat Aug  6 12:54:42 MST 1994
FROM:	valdes

BUG:	If DISPAXIS=2 and one specifies log sampling (ylog=yes)
	then the specified sampling is done correctly but the header
	coordinate description is incorrect.  Specifically the starting
	wavelength, CRVAL2, is given as a linear wavelength rather
	than a log wavelength.  Display of this spectrum, say with
	SPLOT, produces a wavelength scale which is very compressed
	at the starting wavelength.  The workaround is to fix the header
	of the transformed image with

	    cl> hedit  crval2 '(log10(crval2))' update+

	This was caused by a typo where parameter xlog was used
	where ylog should have been.  Another thing to be aware
	of is that extraction of a 1D spectrum from the 2D
	spectrum with the APEXTRACT tasks will propagate the error.
	For such data SPLOT crashes because it tries to evaluate
	an impossibly large decimal exponent.

STATUS:	Fixed in versions after V2.10.2