Gunma Prefectural Observatory - Japan's Largest Public Observatory with a 150cm Telescope

Overview

Gunma Prefectural Observatory is a large public observatory located at approximately 885 meters elevation in Takayama Village, Agatsuma District, Gunma Prefecture. It houses 150-centimeter and 65-centimeter reflector telescopes in two separate domes, making it one of Japan's largest public-access observatories.

Takayama Village is a member of the "Japan's Most Beautiful Villages" association and places strong emphasis on environmental conservation. The area around the observatory experiences relatively minimal light pollution and combines excellent facilities with favorable observation conditions.

Observation Environment

The observatory, built on a 885-meter hilltop, offers an open vista from south to west. Since Takayama Village itself is a mountainous farm village, artificial light is kept to a minimum. The Bortle scale rating is approximately class 3, providing conditions suitable for naked-eye Milky Way observation.

However, light pollution from the Maebashi and Takasaki areas in the eastern direction has a slight effect, making observations toward the western and southern skies more effective.

Facilities and Equipment

The main 150-centimeter telescope is open to the public during nighttime observation sessions, with professional staff guiding visitors through seasonal celestial objects. The 65-centimeter telescope provides more detailed celestial observation programs.

The outdoor observation plaza features installed binoculars and small telescopes that visitors can operate to search for stars themselves. During the day, solar observations and visits to the exhibition room are available.

Access

About 30 minutes by car from Shibukawa-Ikaho IC on the Kan-Etsu Expressway. The walk from the parking area to the observatory is about 15 minutes along a gentle uphill path. This route is designed with minimal street lighting, allowing you to enjoy the starry sky while walking.

Observation Tips

Night observation sessions are held year-round but are cancelled during poor weather conditions. Check the official website for the day's status before traveling. The walking path from the parking area to the observatory is dark, so a flashlight for illuminating your feet is necessary. Using a red light shows consideration for other observers.