Extreme Adaptive Optics Imaging with a Clear and Well-Corrected Off-Axis Telescope Subaperture
Abstract
Rather than using an adaptive optics (AO) system to correct a telescope's entire pupil, it can instead be used to more finely correct a smaller subaperture. Indeed, existing AO systems can be used to correct a subaperture 1/3 to 1/2 the size of a 5-10 m telescope to extreme adaptive optics (ExAO) levels. We discuss the potential performance of a clear off-axis well-corrected subaperture (WCS), and describe our initial imaging results with a 1.5 m diameter WCS on the Palomar Observatory's Hale Telescope. These include measured Strehl ratios of 0.92-0.94 in the infrared (2.17 μm) and ≈0.12 in the B band, the latter allowing a binary of separation 0.34" to be easily resolved in the blue. Such performance levels enable a variety of novel observational modes, such as infrared ExAO, visible-wavelength AO, and high-contrast coronagraphy. One specific application suggested by the high Strehl ratio stability obtained (1%) is the measurement of planetary transits and eclipses. Also described is a simple "dark hole" experiment carried out on a binary star, in which a comatic phase term was applied directly to the deformable mirror, in order to shift the diffraction rings to one side of the point-spread function.
Additional Information
Copyright is not claimed for this article. Received 2006 June 30; accepted 2006 December 14. This work was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration, and is based in part on observations obtained at the Hale Telescope, Palomar Observatory, as part of a continuing collaboration between the California Institute of Technology, NASA/JPL, and Cornell University. We thank the staff of the Palomar Observatory for their able and ready assistance, and the JPL Research and Technology Development program for funding this work. Finally, we thank the referee, whose name cannot be spoken, for numerous helpful comments.Attached Files
Published - SERapj07.pdf
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- CaltechAUTHORS:20091112-085921561
- NASA
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2009-11-23Created from EPrint's datestamp field
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2021-11-08Created from EPrint's last_modified field