Space Telescope Science Institute  13.12 Mode = ACCUM Config = COS/NUV 13.14 COS Spectral Elements and Central Wavelengths

REFERENCE INFORMATION

13.13 COS Apertures

Valid COS apertures are listed in Table 13.2 below. Science observations should use the PSA or BOA apertures. The BOA aperture is the same size as the PSA but contains a neutral-density filter that attenuates the source by a factor of ~200. The WCA is intended for wavelength calibrations using the WAVE target.


Table 13.2: COS Apertures
Aperture
Definition
Size
Usage
PSA
Primary Science Aperture
2.5 arc-seconds
Default science aperture
BOA
Bright Object Aperture
2.5 arc-seconds
Contains neutral density filter (ND2) for bright objects
WCA
Wavelength Calibration Aperture
20 microns (dispersion) x 100 microns (cross-dispersion)
Wavelength Calibrations
13.12 Mode = ACCUM Config = COS/NUV 13.14 COS Spectral Elements and Central Wavelengths
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