Asiatic Researches or Transactions of the Society Instituted in Bengal, for Inquiring Into the History and Antiquities, the Arts, Sciences, and Literature, of Asia Volume 16

Asiatic Researches or Transactions of the Society Instituted in Bengal, for Inquiring Into the History and Antiquities, the Arts, Sciences, and Literature, of Asia Volume 16

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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. 1828 edition. Excerpt: ...&c. But the transit instrument is not susceptible of any instrumental error that may not be obviated. When the instrument is accurately adjusted to the meridian, it will be advisable for the beginner to select from the catalogues, those stars which he thinks best adapted, allowing an interval of at least 3m. or 4a. between each. He should make a list of them under the heads of their names. Right ascensions for the beginning of the year, and their declinations and altitudes; since by means of the computed altitudes, the instrument is elevated to the same altitude on the circle, and he will find the star to be observed, in the field view of the telescope. Having observed the transit of the first star, the difference in right ascension of those that follow, will indicate nearly the time that will elapse before the second or third star may be expected to appear in the field view. When the observer becomes accustomed to the instrument, and expert in directing it, and in noting the times of transit, he may then observe the transit of as many stars as can be done conveniently, within a given distance from the equator, by merely giving the instrument a sweep slowly along the meridian, noting the times of transit and the altitude, or zenith distance of each star on the circle. From the altitudes, he computes the approximate declination of the star, and knowing also, from the time of its transit, the approximate right ascension of the star, he will, on reference to the catalogues, be able to discover its name and character. It may, however, be laid down as a rule, that when an observer can select from ten to fifteen or twenty good stars, that is, stars whose right ascensions have been recently determined, some before and some after the moon's...show more

Product details

  • Paperback | 150 pages
  • 189 x 246 x 8mm | 281g
  • Rarebooksclub.com
  • United States
  • English
  • black & white illustrations
  • 1236879120
  • 9781236879127