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multiple-etalon systems for the advanced technology solar telescopeMultiple etalon systems are discussed that meet the science requirements for a narrow-passband imaging system for the 4-meter National Solar Observatory (NSO)/Advance Technology Solar Telescope (ATST). A multiple etalon system can provide an imaging interferometer that works in four distinct modes: as a spectro-polarimeter, a filter-vector magnetograph, an intermediate-band imager, and broadband high-resolution imager. Specific dual and triple etalon configurations are described that provide a spectrographic passband of 2.0-3.5 micron and reduce parasitic light levels to 10(exp -4) as required for precise polarization measurement, e.g., Zeeman measurements of magnetic sensitive lines. A TESOS-like (Telecentric Etalon SOlar Spectrometer) triple etalon system provides a spectral purity of 10(exp -5). The triple designs have the advantage of reducing the finesse requirement on each etalon; allow the use of more stable blocking filters, and have very high spectral purity. A dual-etalon double-pass (Cavallini-like) system can provide a competing configuration. Such a dual-etalon design can provide high contrast. The selection of the final focal plane instrument will depend on a trade-off between an ideal instrument and practical reality. The trade study will include the number of etalons, their aperture sizes, complexities of the optical train, number of blocking filters, configuration of the electronic control system, computer interfaces, temperature controllers, etalon controllers, and their associated feedback electronics. The heritage of single and multiple etalon systems comes from their use in several observatories, including the Marshall Space Flight Center (MSFC) Solar Observatory, Sacramento Peak Observatory (NSO), and Kiepenheuer-Institut fur Sonnenphysik (KIS, Germany), Mees Solar Observatory (University of Hawaii), and Arcetri Astrophysical Observatory (Italy). The design of the ATST multiple etalon system will benefit from the experience gained at these observatories.
Document ID
Document Type
Reprint (Version printed in journal)
Gary, G. Allen
(NASA Marshall Space Flight Center Huntsville, AL, United States)
Balasubramaniam, K. S.
(National Solar Observatory United States)
Sigwarth, Michael
(Kiepenheuer-Inst. fuer Sonnenphysik Freiburg, Germany)
Date Acquired
August 21, 2013
Publication Date
January 1, 2003
Publication Information
Publication: Innovative Telescopes and Instrumentation for Solar Astrophysics
Volume: 4853
Subject Category
Instrumentation and Photography
Meeting Information
Proceedings of the SPIE Reprint(Waikoloa, HI)
Distribution Limits