SYSTEM: V2.9
NUMBER: 129 MODULE: onedspec.splot, onedspec.calibrate SYSTEM: V2.9 DATE: Tue Jul 10 17:07:46 MST 1990 FROM: valdes BUG: In SPLOT the first pixel is ignored. In CALIBRATE the wavelength scale for extinction correction will be in error by one pixels. STATUS: These two bugs are related because the header parameter NP1, which is the offset to the first valid pixel, should be zero in most cases but a bug fix in Nov. 1989 put in a minimum value of 1. The symptom in SPLOT is to lose the first pixel but the wavelength scale is correctly compensated. In CALIBRATE the wavelength scale is not compensated though the error should be extremely small since the calibrations are interpolations from a smooth curve. There is no easy work around for SPLOT. If the one pixel wavelength error in CALIBRATE is a concern one could reset the wavelength zero point parameter W0 or CRVAL1 to be greater by WPC or CDELT1; i.e. make the starting wavelength parameter refer to pixel 2. Note that this will make the wavelengths wrong for SPLOT and other ONEDSPEC tasks. This bug is corrected in V2.10.