We found a match
Your institution may have access to this item. Find your institution then sign in to continue.
- Title
Integral field unit for the existing imaging and spectroscopy instrument, FOCAS.
- Authors
Ozaki, Shinobu; Fukushima, Mitsuhiro; Iwashita, Hikaru; Mitsui, Kenji; Hattori, Takashi; Lee, Chien-Hsiu; Tanaka, Yoko; Tsuzuki, Toshihiro; Miyazaki, Satoshi; Yamashita, Takuya; Okada, Norio; Obuchi, Yoshiyuki
- Abstract
The Faint Object Camera and Spectrograph (FOCAS) is an optical imaging and spectroscopy instrument for the Subaru Telescope. It has been a workhorse instrument since the first-light phase of the telescope. We describe an integral field unit (IFU) that has recently been installed in FOCAS. The IFU utilizes an image slicer that divides a |${13{^{\prime \prime }_{.}}5}$| × |${10{^{\prime \prime }_{.}}0}$| field of view into 23 stripes, with a width of |${0{^{\prime \prime }_{.}}435}$|. A sky spectrum separated from an object by approximately |${5{^{\prime }_{.}}2}$| can be obtained at the same time as an object spectrum. Test observations confirmed that the image quality of the IFU does not degrade the |${0{^{\prime \prime }_{.}}435}$| sampling, and that slice width and length are consistent with the design. Highly reflective multilayer dielectric coatings were coated on all the mirrors in the IFU, thereby offering a high mean IFU throughput of ∼85% over the field. However, the outer part of the field showed throughput degradation, which was mainly caused by vignetting as a result of misalignment. The flat-fielding accuracy was degraded by the vignetting, with the variation depending on the direction of the telescope.
- Subjects
SPECTRAL imaging; OPTICAL spectroscopy; INTEGRALS; SPECTROGRAPHS; OPTICAL images
- Publication
Publications of the Astronomical Society of Japan, 2020, Vol 72, Issue 6, p1
- ISSN
0004-6264
- Publication type
Article
- DOI
10.1093/pasj/psaa092