Gemini planet imager observational calibrations VIII: Characterization and role of satellite spots

Jason J. Wang, Abhijith Rajan, James R. Graham, Dmitry Savransky, Patrick J. Ingraham, Kimberly Ward-Duong, Jennifer Patience, Robert J. De Rosa, Joanna Bulger, Anand Sivaramakrishnan, Marshall D. Perrin, Sandrine J. Thomas, Naru Sadakuni, Alexandra Z. Greenbaum, Laurent Pueyo, Christian Marois, Ben R. Oppenheimer, Paul Kalas, Andrew Cardwell, Stephen GoodsellPascale Hibon, Fredrik T. Rantakyrö

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

55 Scopus citations


The Gemini Planet Imager (GPI) combines extreme adaptive optics, an integral field spectrograph, and a high performance coronagraph to directly image extrasolar planets in the near-infrared. Because the coronagraph blocks most of the light from the star, it prevents the properties of the host star from being measured directly. Instead, satellite spots, which are created by diffraction from a square grid in the pupil plane, can be used to locate the star and extract its spectrum. We describe the techniques implemented into the GPI Data Reduction Pipeline to measure the properties of the satellite spots and discuss the precision of the reconstructed astrometry and spectrophotometry of the occulted star. We find the astrometric precision of the satellite spots in an H-band datacube to be 0.05 pixels and is best when individual satellite spots have a signal to noise ratio (SNR) of > 20. In regards to satellite spot spectrophotometry, we find that the total flux from the satellite spots is stable to ∼7% and scales linearly with central star brightness and that the shape of the satellite spot spectrum varies on the 2% level.

Original languageEnglish (US)
Title of host publicationGround-Based and Airborne Instrumentation for Astronomy V
EditorsSuzanne K. Ramsay, Ian S. McLean, Hideki Takami
ISBN (Electronic)9780819496157
StatePublished - 2014
EventGround-Based and Airborne Instrumentation for Astronomy V - Montreal, Canada
Duration: Jun 22 2014Jun 26 2014

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X
ISSN (Electronic)1996-756X


OtherGround-Based and Airborne Instrumentation for Astronomy V


  • GPI
  • Gemini Planet Imager
  • astrometry
  • exoplanets
  • high contrast imaging
  • spectrophotometry

ASJC Scopus subject areas

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


Dive into the research topics of 'Gemini planet imager observational calibrations VIII: Characterization and role of satellite spots'. Together they form a unique fingerprint.

Cite this