Dōdaira Observatory 'Star and Green Creation Center' — Experience authentic stargazing with the former National Astronomical Observatory's 91cm telescope

Overview

Dōdaira Observatory "Star and Green Creation Center" is a celestial observation and accommodation facility at the summit of Dōdaira Mountain (elevation 875.8m) in Tokigawa Town, Hiki County, Saitama Prefecture. Once used as an observation facility of the Tokyo Astronomical Observatory of Tokyo University (now National Astronomical Observatory), the 91cm reflector telescope remains operational.

The major appeal is its accessibility from Tokyo (about 2 hours by car) and the availability of accommodation facilities.

Observation environment

The summit of Dōdaira Mountain has an open surrounding landscape, with especially excellent views from the south to west. At 875m elevation, positioned between the Chichibu Mountains and the Kanto Plains, the northern sky opens to the darker Chichibu direction.

However, from south to east, light pollution from the Kanto Plains affects observations. While not matching the darkness of Hokkaido or Nagano highlands, conditions are incomparably better than urban areas, and on good nights, the Milky Way is visible.

Facilities and equipment

The main feature is the 91cm reflector telescope, available during stargazing events held twice monthly with expert commentary. Reservations are required.

Accommodation facilities include Mongolian tents, log houses, and bungalows, suitable for families and groups. Overnight guests can enjoy stargazing throughout the night for dedicated observation sessions.

Access

About 50-60 minutes by car from Matsumoda IC or Arashiyama-Ogawa IC on the Kan-Etsu Expressway. The access road to the summit is paved but has narrow sections requiring caution with oncoming traffic. Public transportation access is difficult, so car visits are essential.

Stargazing tips

Confirm the event schedule on the official website. Early booking is recommended due to high demand. Even without events, you can enjoy the starry sky from the summit parking lot. The summit is often windy, so bring a windproof jacket.