CoCo: an infrared cold coronagraph for astronomical observations

Shu-i Wang; Pamela D. Owensby; Douglas W. Toomey; Robert H. Brown; Werner E. Stahlberger; Charles P. Cavedoni; Rong Hua; Christ Ftaclas

doi:10.1117/12.176765

1 June 1994 CoCo: an infrared cold coronagraph for astronomical observations

Shu-i Wang, Pamela D. Owensby, Douglas W. Toomey, Robert H. Brown, Werner E. Stahlberger, Charles P. Cavedoni, Rong Hua, Christ Ftaclas

Author Affiliations +

Proceedings Volume 2198, Instrumentation in Astronomy VIII; (1994) https://doi.org/10.1117/12.176765
Event: 1994 Symposium on Astronomical Telescopes and Instrumentation for the 21st Century, 1994, Kailua, Kona, HI, United States

Abstract

This paper describes the design of an IR cold coronagraph (CoCo) built by SETS Technology, Inc., for use at the NASA 3 m IR Telescope Facility (IRTF) at Mauna Kea Observatory, for the imaging of faint IR 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 micrometers and uses a 256x256 InSb array. The platescale can be varied from 0.06'/pixel to 0.15'/pixel, 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.

Citation Download Citation

Shu-i Wang, Pamela D. Owensby, Douglas W. Toomey, Robert H. Brown, Werner E. Stahlberger, Charles P. Cavedoni, Rong Hua, and Christ Ftaclas "CoCo: an infrared cold coronagraph for astronomical observations", Proc. SPIE 2198, Instrumentation in Astronomy VIII, (1 June 1994); https://doi.org/10.1117/12.176765

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