Mount Palomar Observatory was an astronomical observatory on Earth.

In the 1970s, when Downphilly detected a large object approaching Earth, Mount Palomar Observatory investigated, but since the object (a Zeron spacecraft) was made of reverse matter, they found nothing. (COMIC: The Enemy from Nowhere)

In December 1986, the observatory offered the first pictures of the planet Mondas entering the solar system to International Television News. (TV: The Tenth Planet)