First Paschen alpha imaging from the ground: The first light of Atacama Near-Infrared Camera on the miniTAO 1m telescope

Kentaro Motohara, Masahiro Konishi, Koji Toshikawa, Natsuko Mitani, Shigeyuki Sako, Yuka K. Uchimoto, Tomoyasu Yamamuro, Takeo Minezaki, Toshihiko Tanabe, Takashi Miyata, Shintaro Koshida, Daisuke Kato, Ryo Ohsawa, Tomohiko Nakamura, Kentaro Asano, Yuzuru Yoshii, Mamoru Doi, Kotaro Kohno, Masuo Tanaka, Kimiaki KawaraToshihiro Handa, Tsutomu Aoki, Takao Soyano, Ken'Ichi Tarusawa, Yoshifusa Ita

Research output: Chapter in Book/Report/Conference proceedingConference contribution

18 Citations (Scopus)


We have developed a near infrared camera called ANIR (Atacama Near InfraRed camera) for the University of Tokyo Atacama 1.0m telescope installed at the summit of Co. Chajnantor (5640m altitude) in northern Chile. The camera is based on a PACE HAWAII-2 array with an Offner relay optics for re-imaging, and field of view is 5'. 3 × 5'. 3 with pixel scale of 0''. 31/pix. It is also capable of optical/infrared simultaneous imaging by inserting a dichroic mirror before the focal plane. The high altitude and extremely low water vapor (PWV=0.5mm) of the site enables us to perform observation of hydrogen Paschenα (Paα) emission line at 1.8751 μm. The first light observation was carried out in July 2009, and we have successfully obtained Paα images of the Galactic center using the N1875 narrow-band filter. This is the first success of Paα imaging of a Galactic object from a ground based telescope. System efficiencies for the broad-band filters are measured to be 15% at the J-band and 30% at Ks, while that of the N1875 narrow-band filter, corresponding to Paα; wavelength, varies from 8 to 15%, which may be caused by fluctuation of the atmospheric transmittance. ATRAN simulation suggests that this corresponds to PWV of 0.3 - 1.5mm, consistent with previous results of the site testing. Measured seeing size is median ∼0''. 8, corresponding to the real seeing value of 0''. 6 - 0''. 8. These results demonstrates the excellent capability of the site for infrared observations.

Original languageEnglish
Title of host publicationGround-Based and Airborne Instrumentation for Astronomy III
EditionPART 1
Publication statusPublished - 2010
EventGround-Based and Airborne Instrumentation for Astronomy III - San Diego, CA, United States
Duration: 2010 Jun 272010 Jul 2

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
NumberPART 1
ISSN (Print)0277-786X


OtherGround-Based and Airborne Instrumentation for Astronomy III
Country/TerritoryUnited States
CitySan Diego, CA


  • Atacama
  • Co. Chajnantor
  • PWV
  • Paschen alpha
  • imager
  • near infrared

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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