Externally occulted terrestrial planet finder coronagraph: Simulations and sensitivities

Richard G. Lyon, Sally Heap, Amy Lo, Webster Cash, Glenn D. Starkman, Robert J. Vanderbei, N. Jeremy Kasdin, Craig J. Copi

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

14 Scopus citations


A multitude of coronagraphic techniques for the space-based direct detection and characterization of exo-solar terrestrial planets are actively being pursued by the astronomical community. Typical coronagraphs have internal shaped focal plane and/or pupil plane occulting masks which block and/or diffract starlight thereby increasing the planet's contrast with respect to its parent star. Past studies have shown that any internal technique is limited by the ability to sense and control amplitude, phase (wavefront) and polarization to exquisite levels - necessitating stressing optical requirements. An alternative and promising technique is to place a starshade, i.e. external occulter, at some distance in front of the telescope. This starshade suppresses most of the starlight before entering the telescope - relaxing optical requirements to that of a more conventional telescope. While an old technique it has been recently been advanced by the recognition that circularly symmetric graded apodizers can be well approximated by shaped binary occulting masks. Indeed optimal shapes have been designed that can achieve smaller inner working angles than conventional coronagraphs and yet have high effective throughput allowing smaller aperture telescopes to achieve the same coronagraphic resolution and similar sensitivity as larger ones. Herein we report on our ongoing modeling, simulation and optimization of external occulters and show sensitivity results with respect to number and shape errors of petals, spectral passband, accuracy of Fresnel propagation, and show results for both filled and segmented aperture telescopes and discuss acquisition and sensing of the occulter's location relative to the telescope.

Original languageEnglish (US)
Title of host publicationUV/Optical/IR Space Telescopes
Subtitle of host publicationInnovative Technologies and Concepts III
StatePublished - 2007
EventUV/Optical/IR Space Telescopes: Innovative Technologies and Concepts III - San Diego, CA, United States
Duration: Aug 26 2007Aug 29 2007

Publication series

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


OtherUV/Optical/IR Space Telescopes: Innovative Technologies and Concepts III
Country/TerritoryUnited States
CitySan Diego, CA

All Science Journal Classification (ASJC) codes

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


  • Beam propagation
  • Coronagraphy
  • Exo-solar
  • Fourier optics
  • Occulters
  • Starshade
  • Terrestrial planets


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