C. Donald Shane telescope

The C. Donald Shane telescope is a 120-inch (3.05-meter) reflecting telescope located at the Lick Observatory in San Jose, California. It was named after astronomer C. Donald Shane in 1978, who led the effort to acquire the necessary funds from the California 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 namesC. Donald Shane telescope
Named afterC. Donald Shane 
Part ofLick Observatory 
Location(s)Santa Clara County, California
Coordinates37°20′35″N 121°38′14″W
First light1959
Telescope styleoptical telescope 
Websitewww.ucolick.org/public/telescopes/shane.html,%20https://www.ucolick.org/main/science/telescopes/shane.html
Location of C. Donald Shane telescope
Related media on Wikimedia Commons

The Shane's mirror started as a 10,000-pound Corning Labs glass test blank for the Palomar 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 to Mount 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 early adaptive optics system.[1]

Features

The telescope can be used with three different focal stations: wide field prime focus, coudé focus for high precision spectroscopy, or the intermediate cassegrain focus.

In the Shane dome there is a laser, 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 the Lawrence Livermore National Laboratory. LAO corrects for atmospheric turbulence either by using a natural guide star or by creating a sodium laser 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 from space-based telescopes. Adaptive optics using natural guide stars has been in development since 1996, and using laser guide stars since 2001. Similar laser adaptive optics systems based on LAO have been installed on the University of California's two Keck telescopes in Hawaii.

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 of stars, supernovae, galaxies, and active galactic nuclei
  • The Hamilton Spectrograph, an echelle spectrograph used for stellar spectroscopy and detection of exoplanets
  • The Shane Adaptive optics infra-Red Camera Spectrograph (ShARCS), an infrared camera used with the Shane adaptive optics system[4]

History

The dome housing the Shane telescope
Shane dome among the mountain top facilitates
Detail of lower truss

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, and ground to its figure at optical shops on the mountain.[5]

For Lick Observatory's first 55 years of operation, its astronomers 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 Palomar Hale Telescope.

An adaptive optics system for the Shane was developed, utilizing a 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 on exoplanets 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]

Contemporaries on commissioning

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

# Name /
Observatory
Image Aperture Altitude First
Light
Special advocate
1 Hale Telescope
Palomar Obs.
200 inch
508 cm
1713 m
(5620 ft)
1948 George Ellery Hale
John D. Rockefeller
2 Shane Telescope
Lick Observatory
120 inch
305 cm
1283 m
(4209 ft)
1959 Nicholas Mayall
C. Donald Shane
3 Hooker Telescope
Mount Wilson Obs.
100 inch
254 cm
1742 m
(5715 ft)
1917 George Ellery Hale
Andrew Carnegie
4 Otto Struve Telescope
McDonald Obs.
82 inch
210 cm
2,070 m
6791 ft
1939 Otto Struve

See also

References

  1. Mt. Hamilton Telescopes: Carnegie Double Astrograph
  2. Lebow, Hilary. "Lick Observatory plans major upgrade for Shane Telescope". UC Santa Cruz News. Retrieved 2019-12-14.
  3. "Lick Observatory Shane Telescope web site". Retrieved 25 January 2017.
  4. McGurk, Rosalie; et al. (2014). "Commissioning ShARCS: the Shane Adaptive optics infraRed Camera-Spectrograph for the Lick Observatory 3-m telescope". Proceedings of the SPIE. 9148: 91483A. arXiv:1407.8205. doi:10.1117/12.2057027. S2CID 118824898. Retrieved 25 January 2017.
  5. "1964PASP...76...77S Page 84". articles.adsabs.harvard.edu. Bibcode:1964PASP...76...77S. Retrieved 2019-11-18.
  6. Appenzeller, Immo (2012-12-06). Reports on Astronomy: Transactions of the International Astronomical Union Volume XXIIIA. Springer Science & Business Media. ISBN 9789401157629.
  7. Leverington, David (2017). Observatories and Telescopes of Modern Times. Cambridge University Press. ISBN 9780521899932.
  8. Stephens, Tim; Writer 459-2495, Staff. "Lick Observatory celebrates 50th anniversary of Shane Telescope". UC Santa Cruz News. Retrieved 2019-11-18.
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