SYSTEM: V2.10-V2.10.2
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> heditcrval2 '(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