Dodaira Observatory 'Star and Green Creation Center' — Full-Scale Astronomy Experience at a Former National Observatory in Japan

Overview

Dodaira Observatory "Star and Green Creation Center" is a celestial observation and accommodation facility located at the peak of Dodaira Mountain (elevation 875.8 m) in Tokigawa, Hiki County, Saitama Prefecture, Japan. Once used as an observation station by Tokyo University's Tokyo Astronomical Observatory (now the National Astronomical Observatory), it retains its 91cm reflecting telescope, which remains fully operational.

The facility's appeal lies in its convenient access—about 2 hours from Tokyo—combined with comprehensive accommodation options.

Observation Environment

The peak of Dodaira Mountain has an open surroundings with excellent views, particularly to the south and west. At an elevation of 875 meters, positioned between the Chichibu Mountains and the Kanto Plain, the site benefits from dark skies to the north. However, southern and eastern views are affected by light pollution from the Kanto Plain, so stargazing cannot match observatories in Hokkaido or the Nagano highlands. Still, the sky is incomparably darker than in urban areas, and the Milky Way is visible on favorable nights.

Facilities and Equipment

The 91cm reflecting telescope is the primary feature, available during biweekly stargazing events by reservation. These sessions include explanations from astronomy experts.

Accommodation includes Mongolian tents, log houses, and bungalows, accommodating families and groups. Guests can enjoy uninterrupted stargazing throughout the night.

Access

About 50–60 minutes by car from Kanetsu Expressway's Higashi-Matsuyama IC or Arashiyama-Ogawa IC. The mountain-top access road is paved but has narrow sections requiring caution with oncoming traffic. Public transportation access is limited, making a car essential.

Stargazing Tips

Event dates are listed on the official website. Early reservations are recommended as the venue is popular. Even without paid programs, visitors can enjoy the night sky from the peak parking area. Mountain winds can be strong, so bring a windproof jacket.