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.
| Identifer | oai:union.ndltd.org:arizona.edu/oai:arizona.openrepository.com:10150/622007 |
| Date | 26 July 2016 |
| Creators | Femenía Castellá, Bruno, Serabyn, Eugene, Mawet, Dimitri, Absil, Olivier, Wizinowich, Peter, Matthews, Keith, Huby, Elsa, Bottom, Michael, Campbell, Randy, Chan, Dwight, Carlomagno, Brunella, Cetre, Sylvain, Defrère, Denis, Delacroix, Christian, Gomez Gonzalez, Carlos, Jolivet, Aïssa, Karlsson, Mikael, Lanclos, Kyle, Lilley, Scott, Milner, Steven, Ngo, Henry, Reggiani, Maddalena, Simmons, Julia, Tran, Hien, Vargas Catalan, Ernesto, Wertz, Olivier |
| Contributors | Univ Arizona, Steward Observ, W. M. Keck Observatory (United States), Jet Propulsion Lab. (United States), California Institute of Technology (United States), Univ. of Liège (Belgium), W. M. Keck Observatory (United States), California Institute of Technology (United States), Univ. of Liège (Belgium), California Institute of Technology (United States), W. M. Keck Observatory (United States), W. M. Keck Observatory (United States), Univ. of Liège (Belgium), W. M. Keck Observatory (United States), Univ. of Arizona (United States), Cornell Univ. (United States), Univ. of Liège (Belgium), Univ. of Liège (Belgium), Uppsala Univ. (Sweden), W. M. Keck Observatory (United States), W. M. Keck Observatory (United States), W. M. Keck Observatory (United States), California Institute of Technology (United States), Univ. of Liège (Belgium), W. M. Keck Observatory (United States), W. M. Keck Observatory (United States), Uppsala Univ. (Sweden), Univ. of Liège (Belgium) |
| Publisher | SPIE-INT SOC OPTICAL ENGINEERING |
| Source Sets | University of Arizona |
| Language | English |
| Detected Language | English |
| Type | Article |
| Rights | © 2016 SPIE |
| Relation | http://proceedings.spiedigitallibrary.org/proceeding.aspx?doi=10.1117/12.2233228 |
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