A four mirror anastigmat collimator design for optical payload calibration

Rolt, Stephen; Calcines, Ariadna; Lomanowski, Bart A.; Bramall, David G.

doi:10.1117/12.2232327

A four mirror anastigmat collimator design for optical payload calibration

Rolt, Stephen; Calcines, Ariadna; Lomanowski, Bart A.; Bramall, David G.

Authors

Stephen Rolt

Dr Ariadna Calcines Rosario ariadna.calcines@durham.ac.uk
Head of Optical Design - CfAI

Bart A. Lomanowski

Dr David Bramall d.g.bramall@durham.ac.uk
Mechanical Design Engineer

Contributors

Howard A. MacEwen
Editor

Giovanni G. Fazio
Editor

Makenzie Lystrup
Editor

Natalie Batalha
Editor

Nicholas Siegler
Editor

Edward C. Tong
Editor

Abstract

We present here a four mirror anastigmatic optical collimator design intended for the calibration of an earth observation satellite instrument. Specifically, the collimator is to be applied to the ground based calibration of the Sentinel-4/UVN instrument. This imaging spectrometer instrument itself is expected to be deployed in 2019 in a geostationary orbit and will make spatially resolved spectroscopic measurements of atmospheric contaminants. The collimator is to be deployed during the ground based calibration only and does not form part of the instrument itself. The purpose of the collimator is to provide collimated light within the two instrument passbands in the UV-VIS (305 – 500 nm) and the NIR (750 – 775 nm). Moreover, that collimated light will be derived from a variety of slit like objects located at the input focal (object) plane of the collimator which is uniformly illuminated by a number of light sources. The collimator must relay these objects with exceptionally high fidelity. To this end, the wavefront error of the collimator should be less than 30 nm rms across the collimator field of view. This field is determined by the largest object which is a large rectangular slit, 4.4° x 0.25°. Other important considerations affecting the optical design are the requirements for input telecentricity and the size (85 mm) and location (2500 mm ‘back focal distance’) of the exit pupil. The design of the instrument against these basic requirements is discussed in detail. In addition an analysis of the straylight and tolerancing is presented in detail.

Citation

Rolt, S., Calcines, A., Lomanowski, B. A., & Bramall, D. G. (2016). A four mirror anastigmat collimator design for optical payload calibration. In H. A. MacEwen, G. G. Fazio, M. Lystrup, N. Batalha, N. Siegler, & E. C. Tong (Eds.), Proceedings Volume 9904, Space Telescopes and Instrumentation 2016: Optical, Infrared, and Millimeter Wave. https://doi.org/10.1117/12.2232327

Conference Name	Space Telescopes and Instrumentation 2016: Optical, Infrared, and Millimeter Wave: SPIE Astronomical Telescopes + Instrumentation, 2016
Conference Location	Edinburgh
Online Publication Date	Jul 29, 2016
Publication Date	2016
Deposit Date	Sep 25, 2018
Publicly Available Date	Jan 18, 2023
Volume	9904
Series ISSN	0277-786X
Book Title	Proceedings Volume 9904, Space Telescopes and Instrumentation 2016: Optical, Infrared, and Millimeter Wave
DOI	https://doi.org/10.1117/12.2232327
Public URL	https://durham-repository.worktribe.com/output/1144196

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