The Subaru coronagraphic extreme AO (SCExAO) system: Fast visible imager

Vincent Garrel, Olivier Guyon, Pierre Baudoz, Frantz Martinache, Paul Stewart, Julien Lozi, Tyler Groff

Research output: Chapter in Book/Report/Conference proceedingConference contribution

2 Scopus citations


The Subaru Coronagraphic Extreme Adaptive Optics (SCExAO) system is an instrument designed to be inserted between the Subaru AO188 system and the infrared HiCIAO camera in order to greatly improve the contrast in the very close (less than 0.5″) neighbourhood of stars.Next to the infrared coronagraphic path, a visible scientific path, based on a EMCCD camera, has been implemented. Benefiting from both AO correction and new data processing techniques, it is a powerful tool for high angular resolution imaging and opens numerous new science opportunities. A factor 2 to 3 in Strehl ratio is obtained compared to the AO long exposure time: up to 25% Strehl in the 650nm wavelength, depending on the image processing algorithm used and the seeing conditions. The system is able to deliver diffraction limited images at 650 nm (17 mas FWHM). Our baseline image processing algorithm is based on the selection of the best signal for each spatial frequency. We demonstrate that this approach offers significantly better results than the classical select, shift and add approach (lucky imaging).

Original languageEnglish (US)
Title of host publicationTechniques and Instrumentation for Detection of Exoplanets V
StatePublished - 2011
EventTechniques and Instrumentation for Detection of Exoplanets V - San Diego, CA, United States
Duration: Aug 23 2011Aug 24 2011

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X


OtherTechniques and Instrumentation for Detection of Exoplanets V
Country/TerritoryUnited States
CitySan Diego, CA


  • adaptive optics methods
  • data analysis techniques
  • high angular resolution instrumentation
  • high angular resolution techniques
  • image processing
  • instrumentation

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


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