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Hubble Space Telescope
STIS Sensitivity

Sensitivity degradation is typically less than 2% per year, as seen in plots of sensitivity vs. time for the G140L, G230L and G230LB, G430L, G750L gratings. This time dependence is now incorporated in the STScI data-reduction pipeline for all STIS first-order configurations: it was implemented in May 2002 for the MAMAs (see ISR 2001-01) and on Nov 13, 2003 for the CCD.

New trends in the sensitivity degradation have been observed in the last two years and were incorporated in the pipeline on 2004-Apr-16.

STIS sensitivity can be evaluated interactively using the web-based Exposure Time Calculators (ETCs).

Count rates can also be determined manually from sensitivities, using definitions and formulae in the STIS Instrument Handbook.

Spectroscopic Sensitivity Plots
G140L G230L G230LB G430L G750L
G140M G230M G230MB G430M G750M
E140M E230M      
E140H E230H Prism    

Spectroscopic Sensitivity Tables
G140L G230L G230LB G430L G750L
G140M G230M G230MB G430M G750M
E140M E230M      
E140H E230H Prism    

Imaging Sensitivity Tables
Detector Filter
CCD Clear Long Pass OIII OII
NUV-MAMA Clear
Quartz
CIII
ND3
SrF2
CN182
ND5
MgII
NDQ
CN270
FUV-MAMA Clear
Quartz
ND3
SrF2
ND5
LyA
NDQ

Sensitivity may also be characterized in terms of limiting magnitudes for spectroscopic and imaging modes. These tables list V magnitudes that yield S/N=10 for an A0V stellar input spectrum.