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arXiv · 1105.0997

Grisms Developed for FOCAS

Noboru Ebizuka·Koji S. Kawabata·Keiko Oka·Akiko Yamada·Masako Kashiwagi·Kashiko Kodate·Takashi Hattori·Nobunari Kashikawa·Masanori Iye
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Abstract

Faint Object Camera and Spectrograph (FOCAS) is a versatile common-use optical instrument for the 8.2m Subaru Telescope, offering imaging and spectroscopic observations. FOCAS employs grisms with resolving powers ranging from 280 to 8200 as dispersive optical elements. A grism is a direct-vision grating composed of a transmission grating and prism(s). FOCAS has five grisms with replica surface-relief gratings including an echelle-type grism, and eight grisms with volume-phase holographic (VPH) gratings. The size of these grisms is 110 mm X 106 mm in aperture with a maximum thickness of 110 mm. We employ not only the dichromated gelatin, but also the hologram resin as a recording material for VPH gratings. We discuss the performance of these FOCAS grisms measured in the laboratory, and verify it by test observations, and show examples of astronomical spectroscopic observations.

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Noboru Ebizuka, Koji S. Kawabata, Keiko Oka, Akiko Yamada, Masako Kashiwagi, Kashiko Kodate, Takashi Hattori, Nobunari Kashikawa, Masanori Iye. 2011-05-05. Grisms Developed for FOCAS. https://doi.org/10.1093/pasj%2F63.sp2.s613

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