David G. Monet (U.S. Naval Observatory), The Pan-STARRS Team (Institute for Astronomy, University of Hawaii)
Keywords: Astronomy
Abstract:
The Pan-STARRS PS1 telescope is an alt-az system with two mirrors and three corrector lenses. In order to be able to deliver sub-arcsecond image quality over its very wide field of view (3 deg diameter), the optical elements need to be centered to a precision better than of order 100 microns, and their tilts need be controlled to within 15 arcseconds. Control of the optics configuration is accomplished by static adjustment of the corrector lenses and camera with respect to the instrument rotator, and by real-time active control of the 5 degrees of freedom for both primary and secondary mirrors. In addition, the pneumatic primary mirror support system allows real-time fine control of the mirror figure to correct for astigmatism, tri-foil and other low order aberrations. We have developed software that analyzes shapes of out-of-focus images found across the focal plane and decomposes these into signal-to-noise eigenmodes that allow a determination of any misalignment of the telescope optics, which can then be corrected. We show how this technique has been applied with considerable success to collimate and align the PS1 telescope.
Date of Conference: September 1-4. 2009
Track: Astronomy