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Calibration Status

GHRS Instrument Handbook

The following paragraphs summarize calibrations for the GHRS as of May, 1995. Some items are not applicable to a particular mode ("N/A") and some are to be measured in Cycle 5 ("TBD").

Detector Calibrations

Paired-pulse correction, diode response, and photocathode blemishes have been determined for both detectors. Photocathode response (flat fields) will not be measured, except for G140L (in Cycle 5).


Absolute sensitivity and vignetting have been measured for both the LSA and SSA for G140L, Ech-A, G160M, and G270M. These have also been done for G200M and Ech-B except that LSA vignetting is TBD for G200M and SSA vignetting is TBD for Ech-B. G140M will be characterized completely in Cycle 5.

Scattered light and blaze functions have been determined for both Ech-A and Ech-B.


Line and sample mapping have been done for both detectors and thermal constants have been determined for all the gratings, as have global wavelength coefficients. Incidence angle corrections are available for G160M, G200M, and G270M, but are TBD for the remaining gratings.