iraf.net

NUMBER:	359
MODULE:	calibrate (onedspec, longslit, imred spectral packages)
SYSTEM:	V2.10.3-V2.10.4p2
DATE:	Wed Jan 22 11:18:52 MST 1997
FROM:	valdes

BUG:	The flux calibration of spectra with non-linear dispersion is
	incorrect.  Instead of dividing by the wavelength width of each
	pixel the width of the pixel corresponding to the image line is
	used for all pixels at a given line; (i.e. the width of pixel 2 is
	used for all pixels in the spectrum of the second line in a
	multispec image).  Since a linear dispersion has constant pixel
	width by definition, this bug does not affect linearized spectra.
	The magnitude of the error depends on how non-linear the dispersion
	is; i.e.  how much the widths of the pixels vary.  The workaround
	is to linearize the spectra first with DISPCOR.

STATUS:	Fixed for the next release.