A conceptual scheme for cophasing across gaps in segmented pupils with a laser guide star Fizeau interferometer

Peter Tuthill

doi:10.1117/12.2232385

19 August 2016 A conceptual scheme for cophasing across gaps in segmented pupils with a laser guide star Fizeau interferometer

Peter Tuthill

Author Affiliations +

Proceedings Volume 9907, Optical and Infrared Interferometry and Imaging V; 99070E (2016) https://doi.org/10.1117/12.2232385
Event: SPIE Astronomical Telescopes + Instrumentation, 2016, Edinburgh, United Kingdom

Abstract

Finding and maintaining an accurate cophasing solution for the large primary mirrors which comprise the coming generation of Extremely Large Telescopes has required a significant technological development effort that is still ongoing. Mirrors based on an assembly of a few large segments, such as the Giant Magellan Telescope (GMT – under construction) and the Large Binocular Telescope (LBT – operational) face a particular challenge: elements must be cophased across a gaps ranging from tens of centimeters to meters. Although it is widely believed that laser guide stars are not useful for this specific application, this paper advances a new concept that challenges this orthodoxy. By projecting a Fizeau interference pattern into the sky, and analyzing the form of the backscattered image, it is shown that at least in principle it is possible to cophase across arbitrary gaps.

Citation Download Citation

Peter Tuthill "A conceptual scheme for cophasing across gaps in segmented pupils with a laser guide star Fizeau interferometer", Proc. SPIE 9907, Optical and Infrared Interferometry and Imaging V, 99070E (19 August 2016); https://doi.org/10.1117/12.2232385

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