Zones Of Stars Observed At The United States Naval Observatory With The Meridian Cercle In The Years 1847 1848 And 1849 PDF Download

The zones of stars contained in the following pages were observed with the Meridian Circle in the years 1847, 1848, 1849, and form a continuation of those reduced and published by Mr. James Ferguson, assistant astronomer, in the year 1860. The zones reduced by Mr. Ferguson are those which were observed with this instrument in the year 1846. In his introduction Mr. Ferguson has given a description of the Meridian Circle, and a detailed account of the methods of making and reducing the observations. The description of the instrument will be found also in the annual volume for 1846, page XXXVII. The object-glass of the telescope was 4.5 inches in aperture, and 58.2 inches in focal length. The diaphragm contained eleven transit wires, and sever micrometer-wires for declination. The transit wires were designated 1, 2, I, II, III, IV, V, VI, VII, 10, 11; and the micrometer wires 1, 2, 3, 4, 5, 6, 7. The first of the transit-wires was that first passed by a star, circle east ; and the first of the micrometer-wires was that uppermost in the field, circle east, and the observer looking southward.