We’ve done Mount Wilson, Mullard Radio Astronomy, and the Royal observatories in the past. Here are a few more.
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The Haystack Observatory contains a 120 foot steerable radio dish, was built in 1963, is operated by the US Air Force and MIT, and is used for space surveillance and debris tracking.

The Big Bear Solar Observatory has a 30′ dome, is used only during the day to observe the sun and is operated by National Science Foundation, NASA, NOAA, the Air Force, and the US Navy.

Heyeden Observatory, at Georgetown University, has a 12-inch equatorial telescope used to gather data on variable stars.

The Gaithersburg Latitude Observatory was used from 1899 to 1982 to document variations in the earth’s axis.

Griffith Observatory was built in 1935, is owned by the City of Los Angeles and contains a twelve-inch Zeiss telescope and a coelostat.

The US Naval Observatory contains a 26-inch refracting telescope, was built in 1873, and was used to discover the moons of Mars. It is on the grounds of the Vice President’s residence which probably explains the censoring of the images.

The Cincinnati Observatory was built by Cincinnati College in 1840s and is the oldest proffesional telescope in the US.

These telescopes at UCLA contain 14, 16 and 24-inch telescopes. Note the small planetarium on the roof of the building a short distance to the southwest.

Contributed by Kevin and AlbinoFlea.