National Astronomical Observatory of Japan



Okayama Astrophysical Observatory

Okayama Astrophysical Observatory (OAO) is one of the most important domestic bases for optical-infrared observational astronomy in Japan. OAO operates the 188-cm reflector and promotes its open use. The main research fields being pursued by the 188-cm telescope are stars, interstellar matter, other galaxies, and extrasolar planets. OAO also operates two other telescopes, 91-cm and 50-cm reflectors, with which some original research projects are pursued about the Milky Way structure and variable and active objects. Astronomical instrumentation is another important activity at OAO. An infrared spectrometer and a fiber-link system for the high-resolution optical spectrograph are near completion, and a very wide-field infrared camera is underway. Moreover, OAO promotes domestic inter-university cooperation as well as East Asian astronomical collaborations.


  • 3037-5 Honjou, Kamogata, Asakuchi, Okayama 719-0232, Japan
  • +81-865-44-2155
  • Official Web Site