NEW REPO: https://gitlab.in2p3.fr/ycopin/spectrogrism
This module implements an ad-hoc grism-based spectrograph optical model. It provides a flexible chromatic mapping between the input focal plane and the output detector plane, based on an effective simplified ray-tracing model of the key optical elements defining the spectrograph (collimator, prism, grating, camera), described by a restricted number of physically-motivated distortion parameters.