Lick Observatory

A bequest and a mountain

James Lick, a piano maker and land speculator who became one of California's richest men, left $700,000 in his will to build the world's most powerful telescope, and chose to be buried beneath it. The site, on Mount Hamilton near San Jose at about 1,280 metres, was selected for its clear air and steady seeing, and a road had to be built to reach it. The 36-inch refractor saw first light in 1888, and on 1 June of that year the observatory was transferred to the University of California.

It was the first permanent mountain-top observatory in the world, and it set the pattern: choose the site for the sky, then build the institution around it.

Discoveries by eye and by spectrum

In 1892 Edward Emerson Barnard, using the 36-inch, discovered Amalthea, the fifth moon of Jupiter and the last moon discovered by eye rather than on a photograph. William Campbell and his colleagues made the observatory a centre for spectroscopy, measuring the radial velocities of stars with the Mills spectrograph, and a Lick station in Chile extended the work to the southern sky.

The 36-inch refractor remained the largest in the world until the 40-inch at Yerkes in 1897. The Crossley reflector, a 36-inch given by Edward Crossley, arrived at Lick in 1895 and was used for photography of nebulae and galaxies.

Into the present

The Shane 120-inch telescope was completed in 1959 and was for years among the largest in the world; its mirror and spectrographs are still used. The Automated Planet Finder, a 2.4-metre robotic telescope, entered regular use in 2013 and is used to search for planets. University of California Observatories operates the site, which is also a base for education and public programmes.

Why the mountain won

Before Lick, large telescopes stood in cities and universities, where smoke and light limited what they could do. Mount Hamilton showed that a remote site could pay for itself in the quality of its images, and that an observatory could be a residential community, with astronomers living on the mountain for the length of an observing run. The pattern was copied at Mount Wilson, Palomar and later Maunakea, and the idea of the observatory as a campus above the clouds came from it. The cost was isolation: the road, the water and the power all had to be built and maintained, and the observatory still runs its own infrastructure.

Instruments and technologies

• 36-inch refractor A 91 cm lens by Alvan Clark and Sons, focal length about 17 metres, on an equatorial mount inside a 17-metre dome with a floor that could be raised and lowered.
• Shane 120-inch reflector A 3-metre mirror on an equatorial mount with prime-focus and Cassegrain spectrographs.
• Automated Planet Finder A robotic 2.4-metre telescope feeding a high-resolution echelle spectrometer, designed to measure the small wobbles of stars caused by planets.

The people

• James Lick Donor, buried beneath the 36-inch telescope.
• Edward Emerson Barnard Discoverer of Amalthea; pioneer of astronomical photography.

Timeline

• 1888 First light of the 36-inch refractor and transfer to the University of California.
• 1892 E. E. Barnard discovers Amalthea, Jupiter's fifth moon.
• 1959 Shane 120-inch telescope completed.
• 2013 Automated Planet Finder enters regular use.

Key lessons for observation today

• Site selection is half the instrument Clear, steady air above the haze was why Lick came to be built on a mountain. The same logic governs where sensors, radio telescopes and weather masts are placed.
• Automate what you can repeat The Automated Planet Finder takes observations without a person at the telescope. Remote, automated observing is the standard model for modern networks.
• Endowments need an institution A bequest built the telescope; a university kept it running. Continuity depends on who takes over.

Sources

• Wikipedia, Lick Observatory
• Astronomy, June 1, 1888: Lick Observatory changes hands
• Wikipedia, Edward Emerson Barnard
• Lick Observatory, University of California Observatories