13.3

Gratings

For each COS grating, we present the resolving power, dispersion, plate scale, the wavelength range covered at each central wavelength setting and FP-POS position, sensitivities, effective areas, and a tool for estimating S/N. Advice on use is provided where appropriate.

Note that the quoted sensitivities are estimates for mid-Cycle 21 (April 2014). The COS ETC will be updated as the instrumental sensitivity evolves.

 

Wavelengths in this handbook, and in COS data products, are always measured in vacuum.

 

Gratings:

•	“FUV Grating G130M”

•	“FUV Grating G130M with CENWAVE=1222”

•	“FUV Grating G130M with CENWAVE=1055 or 1096”

•	“FUV Grating G160M”

•	“FUV Grating G140L”

•	“NUV Grating G185M”

•	“NUV Grating G225M”

•	“NUV Grating G285M”

•	“NUV Grating G230L”