Artwork representing the Mt. Palomar Observatory, with one of the biggest optical telescopes in the world. The telescope is situated near Pasadena, United States, at an altitude of 1706m and it was completed in 1947. The telescope has a Cassengrain configuration and the primary mirror (bottom centre) has a diameter of five metres and weighs more than 13 tonnes. The prime focus is situated at 16. 5m from the primary mirror. At the prime focus an observing cage is located inside the narrow cylinder at upper centre where much of the photographic work is done.