CoCo: An infrared cold coronagraph for astronomical observations

Shu I. Wang, Pamela D. Owensby, Robert H. Brown, Werner E. Stahlberger, Charles P. Cavedoni, Rong Hua, Christ Ftaclas

Research output: Contribution to journalConference articlepeer-review

11 Scopus citations


This paper describes the design of an infrared Cold Coronagraph (CoCo) built for use at the NASA 3-m Infrared Telescope Facility (IRTF) at Mauna Kea Observatory, fen the imaging of faint infrared sources in proximity to bright sources. The coronagraph is designed to obtain high contrast photometric images by use of an occulting mask and a pupil mask. The coronagraph is to be used in combination with the IRTF NSFCAM, which covers 1-5 |im and uses a 256×256 InSb array. The platescale can be varied from 0.067pixel to 0.1 V/pixci. covering a field of view of 14" and 38", respectively. Selectable apodized and hard occulting masks are mounted on a wheel as the first element in the system to reduce scattered light Selectable pupil masks are cooled to 77K within the CoCo cryostat. The cryostat consists of a liquid nitrogen can for cooling the optics, masks, and baffles. The CoCo dewar is mounted on a slide in a housing to allow it to move out of the beam path so that the NSFCAM may be used with or without the coronagraph during the same observing period.

Original languageEnglish (US)
Pages (from-to)578-589
Number of pages12
JournalProceedings of SPIE - The International Society for Optical Engineering
StatePublished - Jun 1 1994
Externally publishedYes
EventInstrumentation in Astronomy VIII 1994 - Kailua, Kona, United States
Duration: Mar 13 1994Mar 18 1994

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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