Bisei Astronomical Observatory is the reason many travelers make the detour to Ibara. The hilltop site has a 101-cm telescope and an open deck for looking across the night sky in Bisei, a district known for taking light pollution seriously long before that became fashionable.
Night visits are the prize, but daytime sessions can still be worthwhile if you are curious about the equipment and the landscape. Check the schedule before going; this is a place where a clear evening matters more than a long list of facilities.