The Observatory Volume 25 (Paperback)

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1902 Excerpt: ...of the Sun). Elegant methods are also indicated of obtaining a closer approximation, and of introducing the corrections for parallax and aberration without repeating the whole work ah initio. Two fully worked-out examples are given, viz., Comet 1900 III. and Planet 1900 G.A. The observations used for the comet were made by Mr. Aitken on 1900, Dec. 24, 26, 28; the photographs of the planet were taken on 1900, June 28, 30, July 2. The method seems a very convenient one both for obtaining first approximations to an orbit, and afterwards for correcting them to represent later observations. A. C. D. C. MiNOB Planet Notes.--Three new planets were discovered at Heidelberg on May 7: HX, HY (each of mag. 125) by Wolf, HZ (mag. 12-0) by Camera. The Constant Of Abeeeation.--The evidence that the adopted value of this quantity needs reconsideration is still accumulating. Erom 1857 until the end of the last century, V. Struve's value 2o"-445, found from observations with the prime-vertical transit instrument at Poulkova, was used in the computation for the Nautical Almanac, and in the almanac for the current year 2o"'47 is given as the adopted constant, but many determinations which take account of the variation of latitude tend to show that the value is well above 2o"-5. A recent number of the Astronomical Journal (No. 520) contains two investigations by Dr. Chandler: one, a discussion of observations made by Talcott's method at various latitude-stations, gives 2o"-555 as the value of the constant of aberration; the other, which is a re-examination of Pond's observations of Polaris with the Troughton mural circle, gives 2o"-578 as the value of the same quantity. Dr. Chandler adds that the general mean obtained from an unpublished discussion of ...