MISTRAL is a visible and near infrared imager and spectrograph working with the 1.93m telescope at L'Observatoire de Haute-Provence. The goal of the present project is to design and build one custom lens covering the entire working band 370-1000 nm with an enhanced throughput and resolution. The proposed design has the focal length of 100 mm with f/#=2 and consists of 5 lenses with 2 aspheres. It is capable to work in spectroscopy or direct imaging mode with the spectral resolving power up to R590-1675 or energy concentration of 84% within 1 pixel. The throughput varies from 79 to 98% in the main band of 400-1000 nm with a commercial AR coating and could be yet improved with a custom one. We also demonstrate that with this image quality can be maintained in a <10% margin with practically reachable tolerances.
@article{arxiv.2410.01414,
title = {Design of a custom wideband camera for MISTRAL imager-spectrograph},
author = {Eduard Muslimov and Jerome Schmitt and Christophe Adami and Michel Dennefeld and Marc Ferrari},
journal= {arXiv preprint arXiv:2410.01414},
year = {2024}
}