Abstract
A novel method nicknamed ELASTIC is proposed for the alignment of multiple-aperture telescopes, in particular segmented telescopes. It only needs the acquisition of two diversity images of an unresolved source, and is based on the computation of a modified, frequency-shifted, cross-spectrum. It provides a polychromatic large-range tip/tilt estimation with the existing hardware and an inexpensive noniterative unsupervised algorithm. Its performance is studied and optimized by means of simulations. They show that with 5000 photoelectrons/subaperture/frame and pixel images, residues are within the capture range of interferometric phasing algorithms such as phase diversity. The closed-loop alignment of a 6-subaperture mirror provides an experimental demonstration of the effectiveness of the method.
© 2017 Optical Society of America
Full Article | PDF ArticleMore Like This
Fabien Baron, Isabelle Mocoeur, Frédéric Cassaing, and Laurent M. Mugnier
J. Opt. Soc. Am. A 25(5) 1000-1015 (2008)
Alden S. Jurling and James R. Fienup
J. Opt. Soc. Am. A 31(3) 661-666 (2014)
Matthew R. Bolcar and James R. Fienup
Appl. Opt. 48(1) A5-A12 (2009)