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Hubble Space Telescope
GHRS Instrument Science Report 053

GHRS Instrument Science Report 053

"Using SPYBALs to Improve Pipeline Wavelength Calibrations for the First-Order
Gratings of the GHRS" 

David R. Soderblom, Lisa E. Sherbert and Stephen J. Hulbert

Abstract excerpted from the text:

GHRS ISR-052 showed that wavelengths produced by PODPS can be 
significantly in error compared to the solution that would re-
sult from obtaining a WAVECAL in conjunction with a science ex-
posure. This report illustrates how the information contained in 
Spectrum Y Balance (SPYBAL) exposure, which is routinely obtained
before many GHRS exposures, can be used to correct the default
wavelengths so that they are nearly as good as if a WAVECAL had
been specified. This procedure can also be used with archival