TheC. Donald Shane telescope is a 120-inch (3.05-meter)reflecting telescope located at theLick Observatory inSan Jose,California. It was named after astronomerC. Donald Shane in 1978, who led the effort to acquire the necessary funds from theCalifornia Legislature, and who then oversaw the telescope's construction. It is the largest and most powerful telescope at the Lick Observatory, and was the second-largest optical telescope in the world when it was commissioned in 1959.^[1]

C. Donald Shane Telescope

C. Donald Shane 3m telescope at the Lick observatory on Mt. Hamilton, San Jose, California - as seen from inside the dome.
Alternative names	C. Donald Shane telescope
Location(s)	Santa Clara County,California, Pacific States Region
Coordinates	37°20′35″N121°38′14″W / 37.343036°N 121.637136°W /37.343036; -121.637136
First light	1959
Website	www.ucolick.org/public/telescopes/shane.html,%20https://www.ucolick.org/main/science/telescopes/shane.html
Location of C. Donald Shane telescope
Related media on Commons
[edit on Wikidata]

The Shane's mirror started as a 10,000-pound Corning Labs glass test blank for thePalomar Observatory's 200-inch (5-m)Hale Telescope (in north San Diego County, California), but was sold below cost ($50,000)^[1] by Caltech to the Lick Observatory.^[1] It was then transported toMount Hamilton, where the blank was ground and polished by the observatory.^[1]

The telescope is noted for having three foci, prime focus, Cassegrain focus, and coudé focus.^[1] After several decades of celebrated use, it was also fitted with an earlyadaptive optics system.^[1]

The telescope can be used with three different focal stations: wide fieldprime focus,coudé focus for high precisionspectroscopy, or the intermediatecassegrain focus.

In the Shane dome there is alaser, whose light is sometimes visible with the naked eye, that the observatory beams from the Shane telescope into the night sky. The laser is part of the Lick Adaptive Optics (LAO) program, a joint project of the Lick Observatory and theLawrence Livermore National Laboratory. LAO corrects foratmospheric turbulence either by using a naturalguide star or by creating a sodiumlaser guide star, and using the observed motion of the guide star to direct distortion of a deformable mirror hundreds of times each second. The system produces images that are nearly equivalent to those obtained fromspace-based telescopes.Adaptive optics using natural guide stars has been in development since 1996, and usinglaser guide stars since 2001. Similar laser adaptive optics systems based on LAO have been installed on theUniversity of California's twoKeck telescopes inHawaii.

Operation of the Kast instrument began in 1992, and it was upgraded in the 2010s.^[2] The Kast Double Spectrograph can detect spectrum from near-infrared to near-ultraviolet, and includes two sub-instruments.^[2]

Instrumentation currently in operation at the Shane telescope includes:^[3]

• The Kast Double Spectrograph, used for visible wavelength observations ofstars,supernovae,galaxies, andactive galactic nuclei
• The Hamilton Spectrograph, anechellespectrograph used for stellar spectroscopy and detection ofexoplanets
• The Shane Adaptive optics infra-Red Camera Spectrograph (ShARCS), aninfrared camera used with the Shane adaptive optics system^[4]

After WW2 ended, plans for a large reflecting telescope for the Lick observatory were realized by funding from the State of California in 1946.^[5] A 120 inch glass blank leftover from the Hale telescope was acquired, andground to its figure at optical shops on the mountain.^[5]

For Lick Observatory's first 55 years of operation, itsastronomers relied on two telescopes built in the 19th century. Once considered giants in the field, they had become obsolete. International competition was mounting. The 120-inch reflector addition took 15 years to complete, being completed in 1959. It would be the second-largest telescope in the world, taking its place behind the then World's largest 200-inch PalomarHale Telescope.

An adaptive optics system for the Shane was developed, utilizing an artificial star made by laser and a deformable mirror with actuators.^[6] This AO system was mounted at the f/17 cassegrain focus of the Shane telescope.^[6] The system could send light to a visible-light CCD or an infrared sensor (NICMOS III camera).^[6]

The Shane telescope was tested in 1995 with a sodium laser to make an artificial light for the AO system; the laser utilizes a layer in the atmosphere that reacts with the light.^[7]

In 2009, the Lick Observatory celebrated the fiftieth anniversary of the Shane telescope.^[8] The celebration included a ticketed event with a dinner and a lecture onexoplanets by an astronomer.^[8] In 2014, the observatory received a grant to upgrade the Kast instrument of the Shane telescope.^[9]

In 2015, the company Google donated 1 million USD to the observatory over two years.^[10]

The Shane telescope saw first light to a different world for large telescopes in 1959:

• List of largest optical reflecting telescopes
• List of largest optical telescopes in the 20th century

•   Media related toC. Donald Shane telescope at Wikimedia Commons
• Models of the 120 inch Shane Reflector from the Lick Observatory Records Digital Archive, UC Santa Cruz Library's Digital Collections