National Astronomical Observatory of Japan



Okayama Astrophysical Observatory

Okayama Astrophysical Observatory

Okayama Astrophysical Observatory is on the top of Mt. Chikurinji in Okayama. The observatory has been the center of optical and infrared astronomy research in Japan for over 50 years. The 188-cm Reflector Telescope, the largest reflector in Japan, operates here in addition to the 91-cm Reflector Telescope and the 50-cm Reflector Telescope.

Visitors can see the 188-cm Reflector Telescope through a glass window, panels introducing the research, and the exterior of each dome. It is also possible to look across the vista of the Asakuchi cityscape and the Seto Inland Sea.

Visit Guide

Visitors’ Area
9:00 a.m. to 4:30 p.m.
Annual Open House Day
An open campus event is held one day each year during summer vacation. The event includes opening domes which are normally closed to the public, special lectures, etc.
Special Stargazing Party
Most years, the 188-cm reflector is used to hold star gazing parties in the spring and autumn.
Okayama Astrophysical Observatory


  • 3037-5, Honjo, Kamogata, Asakuchi, Okayama 719-0232, Japan
  • +81-865-44-2155
  • There is no public transportation to the observatory.

Okayama Astronomical Museum

Okayama Astronomical Museum

Okayama Astronomical Museum, managed by Asakuchi City, is located next to Okayama Astrophysical Observatory. Please combine your visit to Okayama Astrophysical Observatory with a visit to this museum.

Open Hours
9:00 a.m. to 4:30 p.m. (Please check the days it is closed at the Okayama Astronomical Museum website.)
Main Facilities / Exhibits
Planetarium, 4D2U Theater, Solar Observation Room, Exhibition Room, etc.
Okayama Astronomical Museum (Japanese)