Results of Micrometer Measures of Double Stars made with the 28-inch Refractor at the Royal Observatory, Greenwich, in the year 1906. (Communicated by the Astronomer Royal.) The measures were made with a bifilar position micrometer on the 28-inch refractor, focal length 28 feet. The power generally employed was 670. When bright stars were observed a blue glass shade was usually employed to diminish the light and irradiation. The observations were made in variously coloured fields or in a dark field with illuminated wires. The initials in the last column are those of the observers, viz. : L. Mr. Lewis W. B. Mr. Bowyer B. Mr. Bryant H. F. Mr. Furner The main portion of the measures are of pairs discovered by Hough, which usually consist of a bright star with a faint companion. The remaining measures are of stars selected from the catalogues of W. Struve, Otto Struve, Burnham, Hussey, and Aitken. In general the present list of measures is confined to stars of which the separation is under 4" or which show orbital motion. The following stars, which are not included in the list of measures, have also been observed. |