In the film a crew of five takes off on the first voyage into space with the Moon as their destination. Somehow they end up off course and make it to Mars. Curiously enough as the rocketship decends to Mars the landscape does bear a resemlance to the real Red Planet. Craters and a dry riverbed can be seen.
Of course any hint of the real Mars is blown away as the intrepid explorers are greeted by a thunderstorm as they touchdown on the Martian surface.
Here is a video clip of the Palomar 200-inch telescope in Rocketship X-M.
The Palomar Observatory has appeared in other science fiction movies (and in novels too!). I'll post some clips from other movies in the near future, but if you know of any science fiction films that show the observatory please send me an email or post them in the comments. Thanks!