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Commissioning and first light results of an L’-band vortex coronagraph with the Keck II adaptive optics NIRC2 science instrument
W. M. Keck Observatory, USA.
Jet Propulsion Laboratory, USA.
California Institute of Technology, USA.
University of Liège, Belgium.
Show others and affiliations
2016 (English)In: Adaptive Optics Systems V / [ed] Marchetti, E; Close, LM; Veran, JP, SPIE - International Society for Optical Engineering, 2016, Vol. 9909, 990922Conference paper, Published paper (Refereed)
Abstract [en]

On March 2015 an L'-band vortex coronagraph based on an Annular Groove Phase Mask made up of a diamond sub-wavelength grating was installed on NIRC2 as a demonstration project. This vortex coronagraph operates in the L' band not only in order to take advantage from the favorable star/planet contrast ratio when observing beyond the K band, but also to exploit the fact that the Keck II Adaptive Optics (AO) system delivers nearly extreme adaptive optics image quality (Strehl ratios values near 90%) at 3.7 mu m. We describe the hardware installation of the vortex phase mask during a routine NIRC2 service mission. The success of the project depends on extensive software development which has allowed the achievement of exquisite real-time pointing control as well as further contrast improvements by using speckle nulling to mitigate the effect of static speckles. First light of the new coronagraphic mode was on June 2015 with already very good initial results. Subsequent commissioning nights were interlaced with science nights by members of the VORTEX team with their respective scientific programs. The new capability and excellent results so far have motivated the VORTEX team and the Keck Science Steering Committee (KSSC) to offer the new mode in shared risk mode for 2016B.

Place, publisher, year, edition, pages
SPIE - International Society for Optical Engineering, 2016. Vol. 9909, 990922
Series
Proceedings of SPIE, ISSN 0277-786X ; 9909
Keyword [en]
WM Keck Observatory, NIRC2, high-contrast imaging, coronagraph, vortex phase mask
National Category
Astronomy, Astrophysics and Cosmology Atom and Molecular Physics and Optics Engineering and Technology
Identifiers
URN: urn:nbn:se:uu:diva-300215DOI: 10.1117/12.2233228ISI: 000387429700063OAI: oai:DiVA.org:uu-300215DiVA: diva2:951120
Conference
SPIE Astronomical Telescopes and Instrumentation, Adaptive Optics Systems V, 26 Jun 26 - JUL 1, 2016, Edinburgh, UNITED KINGDOM
Available from: 2016-08-05 Created: 2016-08-05 Last updated: 2017-01-03Bibliographically approved

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CiteExportLink to record
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