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Hubble Space Telescope
COS Throughput

COS is considerably more sensitive than STIS and earlier-generation HST instruments at comparable spectral resolutions, particularly in the far ultraviolet. At FUV wavelengths, the peak effective area is ~3000 cm2 near 1300 with the G130M grating. At NUV wavelengths, the peak effective area is expected to reach ~850 cm2 near 2250 with the G230L grating.

For further information, see section 5.1.1 of the COS Instrument Handbook.