Our Astronomical Column

Abstract

THE TRANSIT OF MERCURY, MAY 5—6, 1878.—An Appendix to the “Washington Observations, 1876,” is devoted to reports on telescopic observations of this transit and discussions of them. There are individual reports from Professors Asaph Hall, Harkness, Eastman, and Holden, and from Dr. Henry Draper and Mr. H. M. Paul. Probably no other phenomenon of the kind has been watched by so large a number of observers, 109 names appearing in the general record. They were, with very few exceptions, stationed at different points in United States territory. The observations have been calculated by Prof. Eastman and Mr. Paul: the former, attaching greater weight to a certain number made by more experienced observers, finds for the Washington geocentric times those given in the second column below; Mr. Paul deduces for the most probable values those given in the third column (the time of first external contact depending on only two or three observations being omitted; the other contacts depend on 57, 52, and 8 observations respectively):—