Journal article
Alignment and performance verification of two-mirror focal corrector optics using computer-generated holograms for balloon-borne ultraviolet Telescope FIREBall-2
Journal of astronomical telescopes, instruments, and systems, Vol.11(2), 025003
04/20/2025
DOI: 10.1117/1.JATIS.11.2.025003
Abstract
We describe the application of computer-generated holograms (CGHs) for simplifying the optical alignment of a two-mirror focal corrector (FC) assembly for the Faint Intergalactic-medium Redshifted Emission Balloon (FB-2). FB-2 is a joint NASA/Centre National D’Etudes Spatiales-funded suborbital balloon experiment designed to map faint ultraviolet (UV) emission from the circumgalactic medium around low red-shift galaxies. The first flight of FB-2, in September 2018, was interrupted due to a hole in the balloon and could not reach the minimum required altitude for science observations. The gondola landed with high impact, resulting in minor damage to the telescope mirrors and the two-mirror FC assembly. As a result, the FC, a high-conic optical assembly that maps the focal plane of the telescope to the slit mask of the multi-object spectrograph, was misaligned beyond tolerance. FC is a critical subsystem of the FB-2 optical chain as it corrects the aberration from the primary mirror over the wide field of view while preserving the magnification. It was essential to rework and realign FC to enable future FB-2 flights. However, this task is challenging due to the complex optical surfaces, the tight alignment tolerances (<30μm lateral, <1arcmin angular), and the contamination sensitivity of the UV-optimized mirror coatings. We discuss the optical alignment and performance verification scheme that uses CGHs to enable precise realignment of the FC optics while meeting the demanding flight schedule. Our scheme employs two custom CGH nulls combined with a Zygo (Fizeau) interferometer to verify the optical quality of the damaged FC mirror and align the two-mirror system. The successfully re-aligned FC was integrated into the FB-2 spectrograph in early 2023 for a flight in September 2023.
Details
- Title: Subtitle
- Alignment and performance verification of two-mirror focal corrector optics using computer-generated holograms for balloon-borne ultraviolet Telescope FIREBall-2
- Creators
- Simran Agarwal - University of ArizonaAafaque R Khan - University of ArizonaErika Hamden - University of ArizonaHaeun Chung - University of ArizonaDrew M. Miles - California Institute of TechnologyVincent Picouet - California Institute of TechnologyHarrison Bradley - University of ArizonaOlivia Jones - University of ArizonaNazende I. Kerkeser - University of ArizonaChristopher D. Martin - California Institute of TechnologyDavid Schiminovich - Columbia UniversityKeri Hoadley - University of IowaBruno Milliard - Laboratoire d’Astrophysique de MarseilleDavid Valls-Gabaud - Observatoire de ParisMarty Crabill - California Institute of TechnologyZeren Lin - California Institute of Technology
- Resource Type
- Journal article
- Publication Details
- Journal of astronomical telescopes, instruments, and systems, Vol.11(2), 025003
- DOI
- 10.1117/1.JATIS.11.2.025003
- ISSN
- 2329-4124
- eISSN
- 2329-4221
- Publisher
- SPIE-SOC PHOTO-OPTICAL INSTRUMENTATION ENGINEERS; BELLINGHAM
- Grant note
- National Aeronautics and Space Administration under Astrophysics Research and Analysis: 80NSSC20K0395, 80NSSC22K1649 NASA under the Astrophysics Research and Analysis (APRA) program: 80NSSC21K2050 NASA Future Investigators in NASA Earth and Space Science and Technology (FINESST)Zygo CorporationFC alignment activities at UArizona
The authors would like to acknowledge funding from NASA under the Astrophysics Research and Analysis (APRA) program (Grant Nos. 80NSSC20K0395 and 80NSSC22K1649). ARK is funded by the NASA Future Investigators in NASA Earth and Space Science and Technology (FINESST) (Grant No. 80NSSC21K2050). The team at the University of Arizona (UArizona) would like to acknowledge the support from staff at the Steward Observatory, the Lunar Planetary Laboratory, Zygo Corporation, and Arizona Optical Metrology LLC (AOM). We are grateful for the valuable lab and instrument resources provided by Dr. Jared Males, Dr. Laird Close, Dr. Daewook Kim, Dr. Heejoo Choi, and their research groups to support the FC alignment activities at UArizona.
- Language
- English
- Date published
- 04/20/2025
- Academic Unit
- Physics and Astronomy
- Record Identifier
- 9984813157902771
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