PlanetQuest Telescopes

Northern Hemisphere

Beginning in the third quarter of 2005, and in following years, we will be using one of the most famous telescopes in the world at Lick Observatory on Mt. Hamilton—The Crossley. It may be old, but in professional hands and with some upgrades, this instrument is fully capable of making important new discoveries. And there is something extraordinary and special about using historically important telescopes to do cutting-edge science. But we need your help to make this happen. Please consider joining our Old 'Scopes Upgrade Mission to help us undertake some badly needed restoration.  Email for more information.

The Crossley 0.9m Reflecting Telescope (1898), Lick Observatory, Mt. Hamilton, CA

Crossley - Lick Observatory, 1988

The Crossley Telescope at the University of California's Lick Observatory is an f/5.8 reflector and the first large (0.9-meter) modern reflector (metal-on-glass) ever built. It was first used by Andrew Common in 1883 to measure stars photographically in the Orion Nebula that could not be seen with the naked eye. Sold then to Edward Crossley, who donated it to Lick Observatory, it was brought to California in 1895 with the assistance of donors like Wells Fargo (banking), Levi Strauss (clothing), Crocker (banking) and Mills (banking).

In the late 19th century, a series of photographs taken by the then Director of Lick Observatory, James Edward Keeler, showed for the first time that the spiral nebulas were plentiful in all directions of the sky. Spectra of these nebulas taken using the Crossley by Heber Curtis in the decade before 1920 revealed that they showed stellar characteristics (continuum with absorption lines) rather than nebular characteristics (emission lines), essentially demonstrating that they were made up of stars and very far away as opposed to being nearby forming solar systems.

The most recent work on the Crossley—over the past decade—has been the use of wide-field CCD imaging cameras to perform the first thorough search of the circumstellar habitable zone of another star system (the eclipsing binary CM Draconis) using high-precision transit photometry, reaching a detection limit of about 2.3-Earth radii, or at the upper end of actual terrestrial-sized planets, by the TEP (transit of extrasolar planets) observing network.

With an upgraded CCD, field corrector (to a 40-arcminute field of view), and tracking improvements, the Crossley will continue to make a valuable contribution to the PlanetQuest transit search program while still maintaining its Victorian astronomical charm.

For more on the history of the Crossley, see the National Park Service site.


Mt. Teide and Teide Observatory, Canary Islands, the observing site for the PASS project. © Laurance R. Doyle.

The PASS Project Telescopes (Permanent All-Sky Survey), Teide Observatory, Canary Islands

The PASS Project is intended to perform a permanent all-sky survey, obtaining time-series photometry from all bright stars that are visible in one or more observing locations, with the major aim to detect all giant planets transiting bright stars, and to perform a permanent tracking of all bright variable stars. Laurance Doyle is a coinvestigator with principal investigator Hans Deeg on this project, which is still in the construction phase.





Calar Alto Observatory, Spain

We have been invited to join the observing consortium at Calar Alto in Spain ( using a 1.23m telescope, as well as the SMARTS Consortium at Cerro Tololo Inter-American Observatory in Chile (see our Southern Hemisphere page).

Calar Alto Observatory, Spain


14-inch Reflectors

If necessary to obtain additional stars for PlanetQuest transit searches, PlanetQuest may consider building an array of 14-inch robotic reflecting telescopes equipped with CCD cameras to monitor nearby clusters and other sufficiently nearby star fields. These instruments would be capable of reaching down to about 15th magnitude with sufficient precision to detect transiting large extrasolar planets.