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Lick Observatory

telescope, tons, inches, photographic, trustees and visual

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LICK OBSERVATORY, astronomical department of the University of California. James Lick (q.v.), by deeds made in 1874 and 1875, charged a board of trustees to expend the sum of $700,000 for the purpose of purchasing land and constructng °a telescope superior to and more powerful than any telescope yet made . . . and also a suitable observatory . . to be made useful in promoting science." Un der the provisions of this deed a site was se lected in 1876 on the summit of Mount Hamil ton about 26 miles, by road, from San Jose, Cal. The land (about 3,000 acres) was granted at various times by the United States and by the State of California.

Astronomical observations of precision and delicacy require a steady atmosphere as well as a very transparent one, and the site chosen is favorable in both respects. This was thoroughly tested in 1879 by Prof. S. W. Burnham before any buildings were erected. • The first board of trustees (D. 0. Mills, president) chose as chief advisers Profs. Simon Newcomb and Edward S. Holden, and appointed Professor Holden as director. In October 1874 the latter submitted a plan for the building of the ob servatory and a program of work, which were accepted by the trustees, according to which the buildings were constructed and the work carried on from 1874 to 1897. The county of Santa Clara built a fine mountain road to the summit, in 1876, at a cost of $78,000. The work of construction was begun in 1880 by the third board of trustees (Capt. R. S. Floyd, president) with Thomas Fraser as superintend ent. To obtain a level platform for the ob servatory 70,000 tons of rock were blasted from the summit. The instruments were ordered from specifications by Dr. Holden, except the object-glass of the great telescope. After a series of experiments Professor Newcomb ad vised the construction of a refracting telescope for the main instrument of the observatory. The glass discs were founded by Feil and Mantois of Paris and figured by Alvan G. Clark. The finished objective is 36 inches in diameter, and has a focal length of 56 feet 2 inches. Besides the visual objective, there

is a third lens of 33 inches aperture. When this is placed in front of the visual objective the combination becomes a photographic ob ject-glass of 570 inches focal length (the di ameter of the photographic image of the moon is about 5.2 inches). The cost of the visual objective was $50,000, of the photographic cor rector about $13,000, and of the mounting of the telescope about $45,000. The cost of the dome complete was about $85,000; of the whole observatory about $610,000. The mounting of the great telescope was made by Warner and Swasey, of Cleveland. The whole weight of iron pier and mounting is about 37 tons. The moving parts of the latter weigh about seven tons; the tube weighs nearly three tons. The telescope is used for visual purposes, and mi crometer measurements; it is also used for photographic and for spectroscopic observa tions. Its steel dome is 75 feet in diameter, and weighs 100 tons. It was built by the Union Iron Works of San Francisco. The floor of the dome is movable vertically (about 16% feet), according to a plan by Sir Howard Grubb, which ensures a convenient position for the observer, no matter whether the telescope is pointing horizontally or vertically. Other in struments are a 12-inch and a 6-inch refractor, a 4-inch comet-seeker, a 6-inch meridian-circle, a 5-inch photographic telescope, a 4-inch tran sit, a 5-inch photoheliograph, etc.

The great telescope has been in constant use since its erection, and its optical quality has been proved to be excellent. The admirable design and construction of its mounting and dome have much facilitated its work. In 1895 Edward Crossley, M.P., of Halifax, England, presented to the observatory his 3-foot reflector, which has been a powerful auxiliary to the great refractor. The observatory constitutes the Lick Astronomical Department of the Uni versity of California. Its staff has comprised many noted observers: Messrs. Burnham, Bar nard, Schaeberle, Tucker, Perrine, Hussey, Aitken, Wright and others.

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