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Signal-to-noise calculator

S/N ratio to be specified for a reference wavelength of microns

Observation parameters

total exposure time s

Object parameters

Point source with
= mag
W m-2Å-1 at reference wavelength

Extended source with
= mag arcsec-2
W m-2Å-1arcsec-2 at reference wavelength

Telescope and Instrument

Telescope diameter m
Lenslet diameter arcsec
No pixels per resolution element
Grating lines/mm

Background parameters

Seeing FWHM arcsec
Interline sky background photons/s/m2/micron/arcsec2