Telescope at the Lick Observatory, Mount Hamilton in California, USA. This 36 inch refractor telescope (also known as the Great Lick Refractor) was built at the same time as the Lick Observatory, between 1880 and 1888. 36 inches refers to the diameter of the refracting lens, which was, at that time, the largest in the world. The observatory was built 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.