Microarcsecond relative astrometry from the ground with a diffractive pupil

S. Mark Ammons, Eduardo A. Bendek, Olivier Guyon

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

6 Scopus citations

Abstract

The practical use of astrometry to detect exoplanets via the reflex motion of the parent star depends critically on the elimination of systematic noise floors in imaging systems. In the diffractive pupil technique proposed for space-based detection of exo-earths, extended diffraction spikes generated by a dotted primary mirror are referenced against a widefield grid of background stars to calibrate changing optical distortion and achieve microarcsecond astrometric precision on bright targets (Guyon et al. 2010). We describe applications of this concept to ground-based uncrowded astrometry using a diffractive, monopupil telescope and a wide-field camera to image as many as ∼4000 background reference stars. Final relative astrometric precision is limited by differential tip/tilt jitter caused by high altitude layers of turbulence. A diffractive 3-meter telescope is capable of reaching ∼35 μas relative astrometric error per coordinate perpendicular to the zenith vector in three hours on a bright target star (I < 10) in fields of moderate stellar density (∼40 stars arcmin-2 with I < 23). Smaller diffractive apertures (D < 1 m) can achieve 100-200 μas performance with the same stellar density and exposure time and a large telescope (6.5-10 m) could achieve as low as 10 μas, nearly an order of magnitude better than current space-based facilities. The diffractive pupil enables the use of larger fields of view through calibration of changing optical distortion as well as brighter target stars (V < 6) by preventing star saturation. Permitting the sky to naturally roll to average signals over many thousands of pixels can mitigate the effects of detector imperfections.

Original languageEnglish (US)
Title of host publicationTechniques and Instrumentation for Detection of Exoplanets V
DOIs
StatePublished - Oct 11 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
Volume8151
ISSN (Print)0277-786X

Other

OtherTechniques and Instrumentation for Detection of Exoplanets V
CountryUnited States
CitySan Diego, CA
Period8/23/118/24/11

Keywords

  • PECO
  • SIM
  • astrometry
  • differential atmospheric refraction
  • differential tip/tilt jitter
  • diffractive pupil
  • exoearth
  • extrasolar planet
  • microarcsecond

ASJC Scopus subject areas

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

Fingerprint Dive into the research topics of 'Microarcsecond relative astrometry from the ground with a diffractive pupil'. Together they form a unique fingerprint.

  • Cite this

    Ammons, S. M., Bendek, E. A., & Guyon, O. (2011). Microarcsecond relative astrometry from the ground with a diffractive pupil. In Techniques and Instrumentation for Detection of Exoplanets V [81510T] (Proceedings of SPIE - The International Society for Optical Engineering; Vol. 8151). https://doi.org/10.1117/12.894198