Yorii Observatory

Yorii Observatory is a small amateur research facility in Japan, best known for the flurry of minor-planet discoveries made there in the late 1980s. Positioned at 140 metres above sea level, it has quietly added dozens of asteroids to the astronomical record.

About Yorii Observatory

The observatory is run as an amateur research station in Japan, associated with astronomer Hiroshi Mori. Between 1988 and 1991, Mori and fellow observer Masaru Arai used the site to search the sky for previously uncatalogued asteroids, working from coordinates near 36.10°N, 139.24°E.

Telescopes & research

Over those few years, observers at Yorii discovered 45 numbered minor planets, an unusually productive run for a small amateur site. One of them, the carbonaceous asteroid 3823 Yorii, roughly 11 kilometres across, was later named after the observatory itself in recognition of the discoveries made there.

Location & getting there

Yorii Observatory sits in Japan at an elevation of 140 metres. As a privately run amateur site rather than a public visitor centre, its exact access details are best confirmed directly with the observer before planning a trip.

Visiting Yorii Observatory

Because Yorii is a working amateur research station rather than a public attraction, there is no published visitor programme. Anyone hoping to see the site in person should search for current details online before travelling.

See your named star from here

Every star named through Star Register comes with precise coordinates, and any observatory with a telescope can be pointed at those coordinates on a clear night, including a dedicated amateur site like this one. Browse the star catalogue to see how your own named star would appear from the sky above Japan.