HARMONI - the Extremely Large Telescope first light integral field spectrograph: pre-optics: stray light analysis

Garcia, M. A.; Fenés, E. G.; Belenguer, T.; Alonso, A.; García-Lorenzo, B.; Regalado, S.
Bibliographical reference

Ground-based and Airborne Instrumentation for Astronomy IX

Advertised on:
8
2022
Number of authors
6
IAC number of authors
4
Citations
0
Refereed citations
0
Description
HARMONI is the first light visible and near-IR integral field spectrograph for the ELT. It covers a large spectral range from 450nm to 2450nm with resolving powers from 3500 to 18000 and spatial sampling from 60mas to 4mas. The pre-optics take light entering the science cryostat (from the telescope or calibration system), reformatting and conditioning to be suitable for input for the rest of the instrument. In this paper, we present a complete stray light analysis of the HARMONI pre-optics including scattering from optical surface roughness and coatings, unwanted light from mechanical mounts and mechanisms, ghost reflections and scattering from particulate contaminants. Several solutions to reduce this unwanted light are proposed.