# Lunar and Horary Tables, for New and Concise Methods of Performing the Calculations Necessary for Ascertaining the Longitude by Lunar Observations, Or Chronometers: With an Appendix, Containing Directions for Acquiring a Knowledge of the Principal Fixed Stars

Parbury, Allen and Company, 1831 - 20 Seiten

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Seite 44 - C, as seen above, are constants, depending upon the latitude of the place of observation and the declination of the star. Tables for these quantities will be found in an appendix to Annual Report US Coast and Geodetic Survey for 1874.
Seite 10 - Subtract the true altitude of the sun's centre from 90°, and the remainder will be the sun's true meridian zenith distance, which is to be called north or south according as the observer is north or south of the sun at the time of observation.
Seite 5 - ... will be the right ascension of the meridian. From the right ascension of the meridian (increased by 24 hours if necessary) subtract the sun's right ascension...
Seite 18 - Rule. — Find the latitudes of both places; if both be north, or both south, their difference will be the answer; but if one be north and the other south, their sum will be the answer. Exercise.— What is the difference of lat. between Philadelphia and Petersburg? Ans., 20 degrees. Between Madras and Waterford? Am., 39° 13'.
Seite 11 - Then, if the zenith distance and declination be both north or both south, add them together; but if one be north and the other south...
Seite 12 - For ßnding the Latitude by an Altitude of the Polar Star. This table is to be entered with the right ascension of the meridian at the time of observation ; the correction corresponding to which being added to, or subtracted from, the true altitude of the Polar Star, as denoted by the sign + or —, the sum or remainder will give the latitude of the place of observation, which is always North. The table is calculated particularly for the years...
Seite 11 - If the sun or star be at a proper distance from the meridian, the time may be inferred from its altitude...
Seite 6 - Let the apparent distance between the Moon and a Fixed Star be 72° 0
Seite 3 - Stars as follows 1 the first letter of the Greek alphabet being attached to the name of any Constellation points out the brightest Star in that Constellation; the second letter the next in brightness, and so on. When the number of Stars in a Constellation exceeds the number of letters in the Greek alphabet, the letters of the 1talic alphabet are next used, then those of the Roman alphabet, if required 1 and when the number of the remaining Stars are distinguished by means of the common numericals.