I went with a special authorization for a night visit. Past midnight, there is no one and the sky is full of shooting stars. The place reminded me of old sci-fi movies and that made my night really extraordinary.
The observatory is open from 8:30 AM to 5:00 PM and admission is completely free. The self-guided tour course allows visitors to explore the facility at their own pace throughout these hours. There are no reservations required for regular visits, making it easily accessible for spontaneous trips.
Visitors can see the impressive 45-meter Radio Telescope, one of the world's largest radio telescopes, along with the Nobeyama Millimeter Array consisting of six 10-meter diameter telescopes, and the Nobeyama Radioheliograph with eighty-four 80-centimeter antennas. The observatory offers self-guided tours with explanatory panels that help visitors understand the instruments and their role in astronomical research. You can get close-up views of these massive scientific instruments and learn about their discoveries.
The observatory can be reached by car or after a 30-40 minute walk from Nobeyama Station. By public transportation, take the JR Chuo Line to Kobuchizawa Station, then transfer to the JR Koumi Line to reach Nobeyama Station. The facility is located at an elevation of 1,350 meters in the mountains near Minamimaki village in Nagano Prefecture.
Every August, around Saturday the 20th, there is an open gates day with lots of activities. This annual open campus event features additional presentations, demonstrations, and special activities beyond the regular self-guided tour. It's an excellent opportunity for a more comprehensive experience, though the observatory is interesting to visit year-round.
The 45-meter Radio Telescope operates in short-millimeter wavelengths with receivers at multiple frequencies including 1, 2, 3.75, 9.4, 17, 35, and 80 GHz in both left and right polarizations. This facility has contributed to major astronomical discoveries including research on black holes and the formation processes of life-sustaining materials. It's part of the National Astronomical Observatory of Japan and represents some of the most advanced radio astronomy technology in the world.
