Contributions Volume 25-29

Contributions Volume 25-29

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This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1908 edition. Excerpt: ...for parallax of this star and found a value of--o."o18 o."O16. This heliometric result seemed to indicate with certainty that the photographic displacement was not due to parallax, and thereby left the real cause undetermined. It was therefore decided to so plan the work as to obtain four separate positions of ft Cygni corresponding to the mean epochs of Sets (1), (2), (3) and (4). It was hoped that from these results positive conclusions could be drawn. This formed one part of the problem. The other part was the determination of the positions of 43 stars about ft Cygni. This part of the work was divided into four steps as follows: First: An intercomparison of the separate plates of Sets (3) and (4). Second: A reduction of two sets of mean results derived from Sets (3) and (4), using the Astronomische Gesellschaft Catalog as standard. Third: A reduction of two sets of mean results derived from the mean coordinates of Sets (1) and (2) using the mean of the two positions of the stars as obtained in step two as standard. 'Annals N. Y. Acad. Set., VI, May, 1892. A.J., Vol. XII, No. 287, p. 182. s A. /., Vol. XIII, No. 293, p. 37. A.J., Vol. XIII, No. 307, p. 162. Fourth: A reduction of final position from the mean results of steps two and three and a calculation of the precession constants and the magnitudes. Measurement of Plates.--The plates of Series (B) were measured in the spring of 1899 by Miss F. E. Harpham, assisted by Miss Tarbox, in the usual Repsold machine. This machine corresponds very closely to the description given by Scheiner1 of a similar instrument in use at the Leyden Observatory, differing only in that an alteration has been made which obviates "projection errors." This alteration consists of more

Product details

  • Paperback | 34 pages
  • 189 x 246 x 2mm | 82g
  • United States
  • English
  • black & white illustrations
  • 1236993659
  • 9781236993656