Telescope at the Lick Observatory, Mount Hamilton in California, USA. This is the Carnegie telescope, a 20 inch twin reflector telescope and camera built in 1934. It was designed for the Lick Northern Proper Motion survey, a survey of the northern sky carried out over a 50 years. One lens is designed to photograph blue light and the other, yellow light. The Lick Observatory was completed in 1888 at an altitude of 1280 metres and was the world's first permanent mountaintop observatory. Its location provided excellent viewing conditions for years until light pollution from the nearby city of San Jose began to interfere with results.