National Astronomical Observatory of Japan,Mitaka Campus

NAOJ is Japan’s laboratory and inter-university research institute that studies astronomy.
Visitors can see exhibitions about the latest astronomy, the 20-cm Telescope Dome, and the 65-cm Telescope Dome (Observatory History Museum).
An audio guide is available for tours.
Regular stargazing parties are held, and the 4D2U Dome Theater is open to the public. Both stargazing parties and the theatre require reservations.

Audio Guide link
Japanese site https://www.nao.ac.jp/study/mitaka-guide/
English version https://www.nao.ac.jp/study/mitaka-guide/en/