Refractor to enable it to take part in the International Photographic Survey of the Heavens.
Probably the best example of this type of mounting applied to a refractor is that made by the elder Cooke of York for Fletcher of Tarnbank; the polar axis is of cast iron and the mounting very satisfactory and convenient, but unfortunately no detailed description has been published.
Fraunhofer's chef-d'oeuvre, the great Dorpat refractor, made for Otto Struve about 1820, had a mounting of this type, and was the first equatorial of any importance to be provided with clockwork.
The largest example of his work is the refractor of 24-in.
28, 1843) describes a " heliometre-oculaire " which he made for the great Pulkowa refractor, the result of consultations between himself and the elder Struve.
Refractor at Dorpat he discovered a great number of double stars, and published in 1827 a list of all the known objects of this kind (Catalogus novus stellarum duplicium).
Aperture, mounted as a Newtonian telescope (with a silvered plane for the small mirror), when the surfaces are in fair average condition, is equal in light grasp to a first-rate refractor of 10-in.
Refractor for the new observatory at Pulkovo, the only important change made by Fraunhofer's successors was, at Struve's suggestion, the substitution of a stone pier for the wooden stand in the original instrument.
The slow motion in right ascension is defective, being accomplished in the Dorpat refractor by changing the.
Refractor by a handle which, when used, affects very injuriously the rate of the clock for the time being.
This was first accomplished by Grubb in the great refractor of 27-in.
Refractor, of 9-ft.
For the great refractor more recently erected at Potsdam, Messrs Repsold arranged a large platform mounted on a framework which is moved in azimuth by the dome, so that the observer on the platform is always opposite the dome-opening.
The original mounting of the Washington refractor of 26-in.
The eye end presents an refractor appearance too complicated to be figured here; it has a micrometer and its illumination for the position circle, a micrometer head, and a bright or dark field, clamps in right ascension and declination and quick and slow motion in the same, a finder, microscopes for reading the hour and declination circles, an illuminated dial showing sidereal time and driven by an electric current from the sidereal clock, and counter weights which can be removed when a spectroscope or other heavy appliance is added.
Refractor, Hall on the 11th of August 1877, Professor Asaph Hall descried the moons of Mars, Deimos and Phobos; and a minute light-speck, noticed by Professor E.