James Lick telescope

Infobox Telescope
bgcolour =
name = James Lick Telescope


caption = The James Lick Telescope, shown here in an 1889 drawing.
organization = University of California
location = Lick Observatory, San Jose, California, USA
wavelength = optical
built = First light 1888-01-03cite web
last = Misch
first = Tony
authorlink =
coauthors = Remington Stone
title = The Building of Lick Observatory
work = [http://mthamilton.ucolick.org/ Lick Observatory website]
publisher = Univ. of California
year = 1998
url = http://mthamilton.ucolick.org/public/history/bldg_the_obs.html
format =
doi =
accessdate = 2008-06-30]
website = http://mthamilton.ucolick.org/
style = refractor
diameter = 91.44 cm
area =
focal_length = 17.37 m
mounting = equatorial
dome = bi-parting

The James Lick Telescope is an antique refracting 36 inch (91.44 cm) telescope that can still be viewed through today. Also called the "Great Lick Refractor" or simply "Lick Refractor", it is the third-largest refracting telescope in the world, surpassed by the Yerkes Observatory 40-inch and the 1 meter Swedish Solar Telescope. It is located at the University of California's Lick Observatory atop Mount Hamilton at an altitude of 4,209 feet (1,283 m) above sea-level. The telescope is housed inside a dome which is powered by hydraulics to raise and lower the floor, rotate the dome, and drive the clock mechanism to track the earth's rotation. The original hydraulic system still operates today, with the exception that the original wind-powered pumps to fill the reservoirs have been replaced with electric pumps. James Lick is himself entombed below the telescope's observing room's floor.

Here are some excerpts from the July 1902 description of the telescope (out of copyright): Fact|date=February 2007

:The height of the marble floor of the main building above mean sea-level is 4209 feet. On a closely connected peak half a mile to the east of the Observatory, and 50 feet higher, are the reservoirs from which water for household and photographic purposes is distributed. A spring about 350 feet below and one mile to the northeast of the Observatory supplies excellent water. Another peak seven eighths of a mile to the east is the summit of Mount Hamilton; it is 180 feet higher than the Observatory, and supports the reservoirs supplying power for moving the dome, raising the movable floor, and winding the driving clock of the great telescope. This system receives its supply from the winter rains falling on the roofs; the water being pumped to the reservoirs on the higher peak by means of windmills.

:The movable floor in the dome is the first of the kind to be constructed. It is 60 feet in diameter, and can be raised or lowered through a distance of 16 1/2 feet, its purpose being to bring the observer within convenient reach of the eye end of the telescope.

The telescope was the largest refractor until the 1897 construction of the Yerkes telescope, and the second largest up until 2002. The fabrication of the objective lens, a two element achromat, the largest lens ever made at the time, caused years of delay. The famous large telescope maker Alvan Clark 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 making a replacement was delayed. Finally, after 18 failed attempts, the lens was finished, transported safely across country, and on 1888-12-31 was carefully installed in the telescope tube. The builders had to wait for 3 days for a break in the clouds to test it. On the evening of January 3 the telescope saw 'first light' - and they found that the instrument couldn't be focused. An error in the estimate of the lens' focal length caused the tube to be built too long. A hacksaw was sent for, the great tube was unceremoniously cut back to the proper length, and the star Aldebaran came into focus.

Major discoveries

These are some of the discoveries made with the Lick telescope:Fact|date=July 2008

:1. Amalthea, the fifth satellite of Jupiter was discovered in September, 1892. It revolves around the planet once in 11h 57m 22.6s, and is probably about 100 miles in diameter. It is so difficult of observation that, besides members of the Lick Observatory staff, probably not more than twenty persons have seen it.

:2. The speed of the planetary nebulae in their motions through space is of the same order of magnitude as the speed of the stars.

:3. Twenty-five comets - 17 unexpected and 8 periodic - have been discovered.

:4. The unequaled Lick series of comet photographs has taught us more as to the structure, formation, and dissolution of comets' tails than had been learned in all previous time.

:5. About 1300 new double stars have been discovered.

:6. The period of revolution of the double star delta Equulei has been shown to be 53/4 years, the shortest period previously known for any double star being 11.4 years. It is therefore in many ways the most interesting double star under observation.

:7. Spectroscopic observations have shown that the atmosphere of Mars is of low density - probably much less dense at the surface of Mars than the Earth's atmosphere at the summit of the highest peak in the Himalayas.

:8. The speed of the Solar System in its motion through space has been determined by means of the spectroscope to be 121/2 miles per second.

:9. The average speed of the brighter stars is 21 miles per second.

:10. The North Polar Star was found to be a triple star, in 1899, by means of spectroscopic observations. Two of its members are invisible in our largest telescopes. The bright star and one dark companion revolve around each other in four days; and these in turn revolve around the other dark body in several years.

:11. Capella was discovered, in 1899, to be a spectroscopic binary star, period 104 days, the two nearly equal components being inseparable in our largest telescopes.

:12. About 40 spectroscopic binaries - that is, stars seen single in ordinary telescopes, but proven to be double by means of the spectroscope - were discovered in 1898-1902. At least one star in seven has an invisible component, observable thus far only by spectroscopic means.

:13. The Observatory possesses an unequaled series of photographs of the principal nebulae and star clusters.

:14. About 10,000 nebulae have been discovered in the past at the various observatories; but the Lick photographs show that fully 100,000 nebulae await discovery. These photographs led to the unexpected discovery that the majority of the nebulae have a spiral form - undoubted evidence of their rotation.

:15. The Observatory has an extensive set of large-scale photographs of the Solar Corona, secured at four total eclipses. They recorded for the first time the wonderful structure of the inner corona, and furnished invaluable evidence bearing upon the question of the origin of the coronal streamers.

:16. Expeditions from the Lick Observatory successfully observed the following total Solar Eclipses: 1889, in Northern California; 1889, in French Guiana; 1893, in Chili; 1898, in India; 1900, in Georgia; and 1901, in Sumatra.

:17. The light of the inner portion of the Solar Corona is largely inherent, whereas the light of the outer portion is largely reflected sunlight, as proven at the Sumatra eclipse by means of spectroscopic and polariscopic observations.

:18. It has been shown that the principal "New Stars" have been converted into nebulae.

:19. The extraordinary motion in the nebula surrounding Nova Persei was discovered from the photograph of November 7–8, 1901.

:20. Many thousands of very accurate positions of stars have been secured with the Meridian Circle.

:21. Very extensive and accurate observations of Double Stars, Comets, Planets, etc., have been made.

:22. Very extensive additions have been made to our knowledge of the spectra of Nebulae, of Comets, of New Stars, of Bright-Line Stars, etc.

:23. The speeds in the line of sight of about four hundred of the brighter stars in the northern sky have been measured by means of the spectroscope. The results for the various stars lie between the limits of sixty miles approach and sixty miles recession per second. A well-equipped expedition, provided for by Mr. D. O. Mills, will be sent from the Lick Observatory in the summer of 1902 to the vicinity of Santiago, Chili, for the purpose of determining the speeds of the brighter stars in the southern hemisphere of the sky.

References