SPHERE on-sky performance compared with budget predictions
Creators
- Dohlen, Kjetil1
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Vigan, Arthur1
- Mouillet, David2
- Wildi, Francois3
- Sauvage, Jean Francois1
- Fusco, Thierry1
- Beuzit, Jean-Luc2
- Puget, Pascal2
- Le Mignant, David1
- Roelfsema, Ronald4
- Pragt, Johan4
- Schmid, Hands Martin5
- Gratton, Raffaele6
- Mesa, Dino6
- Claudi, Ricardo6
- Langlois, Maud
- Costille, Anne1
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Hugot, Emmanuel1
- O'Neil, Jared7
- Guerra, Juan Carlos7
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N'Diaye, Mamadou8
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Girard, Julien7
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Mawet, Dimitri9
- Zins, Gerard7
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1.
Laboratoire d'Astrophysique de Marseille
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2.
Institut de Planétologie et d'Astrophysique de Grenoble
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3.
University of Geneva
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4.
Netherlands Institute for Radio Astronomy
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5.
ETH Zurich
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6.
Osservatorio Astronomico di Padova
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7.
European Southern Observatory
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8.
Space Telescope Science Institute
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9.
California Institute of Technology
Contributors
Abstract
The SPHERE (spectro-photometric exoplanet research) extreme-AO planet hunter saw first light at the VLT observatory on Mount Paranal in May 2014 after ten years of development. Great efforts were put into modelling its performance, particularly in terms of achievable contrast, and to budgeting instrumental features such as wave front errors and optical transmission to each of the instrument's three focal planes, the near infrared dual imaging camera IRDIS, the near infrared integral field spectrograph IFS and the visible polarimetric camera ZIMPOL. In this paper we aim at comparing predicted performance with measured performance. In addition to comparing on-sky contrast curves and calibrated transmission measurements, we also compare the PSD-based wave front error budget with in-situ wave front maps obtained thanks to a Zernike phase mask, ZELDA, implemented in the infrared coronagraph wheel. One of the most critical elements of the SPHERE system is its high-order deformable mirror, a prototype 40x40 actuator piezo stack design developed in parallel with the instrument itself. The development was a success, as witnessed by the instrument performance, in spite of some bad surprises discovered on the way. The devastating effects of operating without taking properly into account the loss of several actuators and the thermally and temporally induced variations in the DM shape will be analysed, and the actions taken to mitigate these defects through the introduction of specially designed Lyot stops and activation of one of the mirrors in the optical train will be described.
Additional Information
© 2016 Society of Photo-Optical Instrumentation Engineers (SPIE). SPHERE is an instrument designed and built by a consortium consisting of IPAG, MPIA, LAM, LESIA, Laboratoire Fizeau, INAF, Observatoire de Genève, ETH, NOVA, ONERA and ASTRON in collaboration with ESO. We are grateful to all the consortium members who contributed to build, test, and validate the instrument in Europe and in Chile. We also thank the ESO staff involved with the installation and operation of SPHERE on the VLT-UT3.Attached Files
Published - 99083D.pdf
Files
99083D.pdf
Additional details
Identifiers
- Eprint ID
- 74399
- Resolver ID
- CaltechAUTHORS:20170217-082008486
Dates
- Created
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2017-02-18Created from EPrint's datestamp field
- Updated
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2021-11-11Created from EPrint's last_modified field
Caltech Custom Metadata
- Series Name
- Proceedings of SPIE
- Series Volume or Issue Number
- 9908