Development of a 22/43 GHz-band quasi-optical perforated plate and dual-band observation system of the Nobeyama 45 m telescope

Nozomi Okada, Ikumi Hashimoto, Kimihiro Kimura, Takeshi Manabe, Kazuki Tokuda, Toshikazu Onishi, Hideo Ogawa, Hiroshi Imai, Tetsuhiro Minamidani

Research output: Contribution to journalReview articlepeer-review

6 Citations (Scopus)

Abstract

We have developed a system of simultaneous observations in the 22 and 43 GHz bands using the Nobeyama 45 m telescope, and are also working to add the 86 GHz band. Multi-frequency observations are realized by mounting perforated plates in the optics as dichroic frequency-selective devices. This paper presents the development of the perforated plate for the 22 and 43 GHz bands and the results of the commissioning observations with this plate on the Nobeyama 45 m telescope. The perforated plate is designed to be installed in the large telescope optics with a physical beam diameter as large as 50\:cm for transmitting the higher frequency (43 GHz) band and for reflecting the lower frequency (22 GHz) band. The developed plate achieves an insertion loss of 0.22\:dB (5%) at 43\:GHz. The effects of the mounted plate on the systematic offsets and on the accuracy degradation of pointing were confirmed to be negligible. The differences in the main-beam/aperture efficiencies from those without the plate were confirmed to be within a few percent points. In addition, we successfully detected interferometry fringes in a very long baseline interferometry (VLBI) observation using the 45 m telescope and the VLBI Exploration of Radio Astrometry (VERA) 20 m telescopes, which confirmed that the dual-band observation system is operationally effective in both single-dish and VLBI observations.

Original languageEnglish
Article number7
JournalPublications of the Astronomical Society of Japan
Volume72
Issue number1
DOIs
Publication statusPublished - Feb 1 2020
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

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