The James Lick Telescope is a
refracting telescope
A refracting telescope (also called a refractor) is a type of optical telescope that uses a lens (optics), lens as its objective (optics), objective to form an image (also referred to a dioptrics, dioptric telescope). The refracting telescope d ...
built in 1888. It has a lens, which is in diameter—a major achievement in its day. The instrument remains in operation and public viewing is allowed on a limited basis. Also called the "Great Lick Refractor" or simply "Lick Refractor", it was the largest refracting telescope in the world until 1897, and now ranks third, after the 40-inch refractor at the
Yerkes Observatory
Yerkes Observatory ( ) is an astronomical observatory located in Williams Bay, Wisconsin, United States. The observatory was operated by the University of Chicago Department of Astronomy and Astrophysics from its founding in 1897 until 2018. O ...
and the
Swedish 1-m Solar Telescope. (The many larger telescopes in use today are
reflecting telescope
A reflecting telescope (also called a reflector) is a telescope that uses a single or a combination of curved mirrors that reflect light and form an image. The reflecting telescope was invented in the 17th century by Isaac Newton as an alternati ...
s, with a mirror rather than lens as the major optical component.) The telescope is located at the
University of California
The University of California (UC) is a public university, public Land-grant university, land-grant research university, research university system in the U.S. state of California. Headquartered in Oakland, California, Oakland, the system is co ...
's
Lick Observatory
The Lick Observatory is an astronomical observatory owned and operated by the University of California. It is on the summit of Mount Hamilton (California), Mount Hamilton, in the Diablo Range just east of San Jose, California, United States. The ...
atop
Mount Hamilton at an elevation of above sea level. The instrument is housed inside a dome that is powered by hydraulic systems that raise and lower the floor, rotate the dome and drive the clock mechanism to track the Earth's rotation. The original hydraulic arrangement still operates today, with the exception that the original wind-powered pumps that once filled the reservoirs have been replaced with electric pumps.
James Lick is
entombed below the floor of the observing room of the telescope.
Here are some excerpts from an 1894 book describing the telescope:
[''A Brief Account of the Lick Observatory of the University of California''](_blank)
The University Press, 1894.
Construction
The fabrication of the two-element
achromatic objective lens, the largest lens ever made at the time, caused years of delay.
The famous large telescope maker
Alvan Clark
Alvan Clark (March 8, 1804 – August 19, 1887) was an American astronomer and telescope maker.
Biography
Born in Ashfield, Massachusetts, Clark started as a portrait painter and engraver (c.1830s–1850s), and at the age of 40 became involved ...
, was in charge of the optical design. He gave the contract for casting the high quality optical glass blanks, of a size never before attempted, to the firm of Charles Feil in Paris. One of the huge glass disks broke during shipping, and replacing it was delayed. Finally, after 18 failed attempts, the lens was finished, transported safely across country, and on December 31, 1887, was carefully installed in the telescope tube. The builders had to wait for three days for a break in the clouds to test it. On the evening of January 3, the telescope saw
first light,
and users found that the instrument could not be focused—an error in the estimation of the lens'
focal length
The focal length of an Optics, optical system is a measure of how strongly the system converges or diverges light; it is the Multiplicative inverse, inverse of the system's optical power. A positive focal length indicates that a system Converge ...
had caused the tube to be built too long. A
hacksaw
A hacksaw is a fine-toothed saw, originally and mainly made for cutting metal. The equivalent saw for cutting wood is usually called a bow saw.
Most hacksaws are hand saws with a C-shaped walking frame that holds a blade under tension. Suc ...
was procured, the great tube was unceremoniously cut back to the proper length and the star
Aldebaran
Aldebaran () is a star in the zodiac constellation of Taurus. It has the Bayer designation α Tauri, which is Latinized to Alpha Tauri and abbreviated Alpha Tau or α Tau. Aldebaran varies in brightness from an apparent vis ...
came into focus.
Contemporaries on debut
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See also
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List of largest optical telescopes in the 19th century
References
External links
Photographs of the James Lick telescope from the Lick Observatory Records Digital Archive, UC Santa Cruz Library's Digital Collections
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Great refractors
Lick Observatory