Word: instrument
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Dates: during 1880-1889
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...made as far south as 25 degrees beyond the equator, while the expedition sent to South America is completing the observations in the southern hemisphere. A new photographic telescope has been added to the apparatus of the Observatory similar to the 7 inch Bates telescope in Peru. The instrument consists of a telescope with an adjustment for a photographic plate holder...
...lens used is a Voigtlander rectilinear lens, corrected and adapted to the purpose in view. The aperture of the instrument is eight inches and a field of ten degrees square in the heavens can be photographed at one exposure...
Professor Pickering is at present working upon an experiment for ascertaining the exact location of the pole. The instrument used consists of a stationary reflecting telescope with a plate holder suspended in the centre of the aperture upon a pendulum, to avoid any variations of the telescope which might arise from changes of temperature. The movement of the stars revolving about the pole as a centre are photographed upon the plate, and from the races described the location of the pole can be accurately ascertained by geometrical and trigonometry observations...
...telescope for photographing stars has just been completed by Abram Clark and Sons for the Harvard Observatory. The instrument is now in position at the observatory, equatorially mounted while its movements are controlled by clock work which is directly connected with a chronometer in the main building...
...instrument was purchased from the Draper fund and makes a valuable addition to the astronomical department of the university...