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Proceedings Paper • Open Access

Modeling instrumental field-dependent aberrations in the NIRC2 instrument on the Keck II telescope
Author(s): Breann N. Sitarski; Gunther Witzel; Michael P. Fitzgerald; Leo Meyer; Andrea M. Ghez; Randall D. Campbell; Jessica R. Lu; Keith Matthews; Peter Wizinowich; Jim Lyke

Paper Abstract

We present a model of field-dependent aberrations arising in the NIRC2 instrument on the W. M. Keck II telescope. We use high signal-to-noise phase diversity data employing a source in the Nasmyth focal plane to construct a model of the optical path difference as a function of field position and wavelength. With a differential wavefront error of up to 190 nm, this effect is one of the main sources of astrometric and photometric measurement uncertainties. Our tests of temporal stability show sufficient reliability for our measurements over a 20-month period at the field extrema. Additionally, while chromaticity exists, applying a correction for field-dependent aberrations provides overall improvement compared to the existing aberrations present across the field of view.

Paper Details

Date Published: 13 August 2014
PDF: 9 pages
Proc. SPIE 9148, Adaptive Optics Systems IV, 91486T (13 August 2014); doi: 10.1117/12.2057140
Show Author Affiliations
Breann N. Sitarski, Univ. of California, Los Angeles (United States)
Gunther Witzel, Univ. of California, Los Angeles (United States)
Michael P. Fitzgerald, Univ. of California, Los Angeles (United States)
Leo Meyer, Univ. of California, Los Angeles (United States)
Andrea M. Ghez, Univ. of California, Los Angeles (United States)
Randall D. Campbell, W. M. Keck Observatory (United States)
Jessica R. Lu, Institute for Astronomy, Univ. of Hawai'i (United States)
Keith Matthews, California Institute of Technology (United States)
Peter Wizinowich, W. M. Keck Observatory (United States)
Jim Lyke, W. M. Keck Observatory (United States)


Published in SPIE Proceedings Vol. 9148:
Adaptive Optics Systems IV
Enrico Marchetti; Laird M. Close; Jean-Pierre Véran, Editor(s)

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