ESA's Euclid cosmology mission relies on the very sensitive and accurately calibrated spectroscopy channel of the Near-Infrared Spectrometer and Photometer (NISP). With three operational grisms in two wavelength intervals, NISP provides diffraction-limited slitless spectroscopy over a field of 0. 57, deg². A blue grism covers the wavelength range 926--1366, nm at a spectral resolution (of 440--900 for a 0 diameter source with a dispersion of 1. 24, nm, px^-1. Two red grisms span 1206 to 1892, nm at mathcal R =550--740 and a dispersion of 1. 37, nm, px^-1. We describe the construction of the grisms as well as the ground testing of the flight model of the NISP instrument, where these properties were established.
Gillard et al. (Tue,) studied this question.