Share Email Print

Proceedings Paper

Use of field aberrations in the alignment of the Large Binocular Telescope optics
Author(s): A. Rakich; J. M. Hill; C. J. Biddick; D. L Miller; T. Leibold
Format Member Price Non-Member Price
PDF $14.40 $18.00
cover GOOD NEWS! Your organization subscribes to the SPIE Digital Library. You may be able to download this paper for free. Check Access

Paper Abstract

It is now well-known that measurement of field-aberration, and in particular the asymmetric field-astigmatism, is required to break the degeneracy of tip-induced and de-centre-induced aberration that exists when only on-axis misalignment aberrations are considered. This paper discusses the application of the measurement of field-aberrations to the alignment of LBT optics. This application ranges from the use of wide field out-of-focus images to determine corrector tip for the red and blue prime-focus correctors, to the use of data acquired by off-axis Shack-Hartman wavefront sensors to actively reposition the hexapod-mounted primary and secondary mirrors so as to simultaneously remove both de-centre and tip/tilt such that the only remaining field-astigmatism has rotational symmetry about the centre of the detector. Also introduced is a novel method to calculate the misalignment aberrations based on an extension of the plate-diagram analysis. It is shown that this method is readily applicable to the calculation of misalignment aberrations for systems of three-or-more powered mirrors, with almost no more computational difficulty than that of the two-mirror case. Results are discussed, as well as work in progress in this area.

Paper Details

Date Published: 17 July 2008
PDF: 12 pages
Proc. SPIE 7012, Ground-based and Airborne Telescopes II, 70121L (17 July 2008); doi: 10.1117/12.789902
Show Author Affiliations
A. Rakich, Large Binocular Telescope Observatory (United States)
J. M. Hill, Large Binocular Telescope Observatory (United States)
C. J. Biddick, Large Binocular Telescope Observatory (United States)
D. L Miller, Large Binocular Telescope Observatory (United States)
T. Leibold, Large Binocular Telescope Observatory (United States)

Published in SPIE Proceedings Vol. 7012:
Ground-based and Airborne Telescopes II
Larry M. Stepp; Roberto Gilmozzi, Editor(s)

© SPIE. Terms of Use
Back to Top