Onsala Space Observatory was created in 1949.
Onsala's population is 11,951.
The area of Onsala is 10.53 square kilometers.
Onsala's population density is 1,135 people per square kilometer.
It is not an observatory, it simply is an instrument (= a telescope) flying in space, orbiting Earth once in 97 minutes. It is operated from the ground and the "observatory facilities" are on the ground.
Although often called the Montreal Earth Observatory, the space observatory is owned and operated by NASA. The observatory is at the Goddard Space Flight Center in Greenbelt, Maryland.
Jura Observatory was created in 1993.
Detroit Observatory was created in 1854.
Sphinx Observatory was created in 1937.
Ursa Observatory was created in 1926.
Carter Observatory was created in 1937.
Corralitos Observatory was created in 1961.
Stonyhurst Observatory was created in 1838.