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Proceedings Paper

Active optics on the Baade 6.5-m (Magellan I) Telescope
Author(s): Paul L. Schechter; Gregory S. Burley; Charles L. Hull; Matthew Johns; Hubert M. Martin; Skip Schaller; Stephen A. Shectman; Steve C. West
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Paper Abstract

The Magellan active optics system has been operating continuously on the Baade 6.5-m since the start of science operations in February 2001. The active optical elements include the primary mirror, with 104 actuators, and the secondary mirror, with 5 positional degrees of freedom. Shack-Hartmann (SH) wavefront sensors are an integral part of the dual probe guiders. The probes function interchangeably, with either probe capable of guiding or wavefront sensing. In the course of most routine observing stars brighter than 17th magnitude are used to apply corrections once or twice per minute. The rms radius determined from roughly 250 SH spots typically ranges between 0.05" and 0.10". The spot pattern is analyzed in terms of a mixture of 3 Zernike polynomials (used to correct the secondary focus and decollimation) and 12 bending modes of the primary mirror (used to compensate for residual thermal and gravitational distortions). Zernike focus and the lowest order circularly symmetric bending mode, known affectionately as the "conemode," are sufficiently non-degenerate that they can be solved for and corrected separately.

Paper Details

Date Published: 4 February 2003
PDF: 9 pages
Proc. SPIE 4837, Large Ground-based Telescopes, (4 February 2003); doi: 10.1117/12.457899
Show Author Affiliations
Paul L. Schechter, Massachusetts Institute of Technology (United States)
Gregory S. Burley, Carnegie Observatories (United States)
Charles L. Hull, Carnegie Observatories (United States)
Matthew Johns, Carnegie Observatories (United States)
Hubert M. Martin, Steward Observatory/Univ. of Arizona (United States)
Skip Schaller, Las Campanas Observatory (Chile)
Stephen A. Shectman, Carnegie Observatories (United States)
Steve C. West, MMT Observatory (United States)

Published in SPIE Proceedings Vol. 4837:
Large Ground-based Telescopes
Jacobus M. Oschmann; Larry M. Stepp, Editor(s)

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