Just a week after one of the world's great radio telescopes was damaged in a still-unexplained event another is under threat. Unlike the Arecibo radio telescope, the Lick Observatory on Mount Hamilton, in the Diablo Range, California is arguably more important for its historical significance than actual research carried out today, but astronomers still fear its loss.

Lick was the first permanently occupied mountain-top telescope in the world, paving the way for the great modern telescopes. Putting telescopes above a portion of the atmosphere improves their view of the stars, and when Lick was founded in 1887 the skies of California were very dark. The observatory was built at the bequest of James Lick, who is buried beneath where one of the telescopes now stands.

The drawback of such locations is that fires move faster uphill, making the tops of forested mountains hard to defend under conditions like those California is suffering today. In 2003 most of the telescopes at Australia's historic Mount Stromlo Observatory were destroyed by fire, although its visitor center has since been rebuilt.

The original telescope at Lick had an aperture of just 300 millimeters (12 inches); today it is not uncommon for serious amateurs to keep telescopes of that size in their backyard. However, the observatory was fortunate to have E.E. Barnard, one of the most skilled observational astronomers in history, among its first staff. Barnard used the telescope to take some of the earliest photographs of comets and nebulae.

Subsequently, a 91-centimeter (36 inches) telescope was added, which was for nine years the largest in the world. Barnard used this to find the first new moon of Jupiter since Galileo’s four nearly three centuries earlier. Three more of Jupiter's moons were also discovered at Lick.

In 1959 a 300-centimeter (120 inches) aperture telescope was added, once again bringing the observatory to the forefront of global astronomy. However, encroaching light pollution from Silicon Valley means more recent great telescopes have been built elsewhere. Nevertheless, the decision of San Jose to use low-pressure sodium streetlights, which affect astronomy less than broader wavelength alternatives, means research continues from the site, unlike many of the world's other great historical observatories. Prior to the Kepler Space Telescope's launch, Lick was involved in the discovery of a large proportion of the planets known beyond our Solar System.

During its 133 year span, the observatory has survived many dangers, including having a plane crash into the main building in 1939. However, just days ago another part of California set a likely world temperature record, and the heat has fanned fires that pose the observatory's greatest threat.

Fire crews are at the site with the main building being used as a command post. Meanwhile, cameras on the roofs of the visitor's center allow the world to helplessly watch events unfold, refreshing every three minutes.