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aberration absolute zero actual adopted altitude angle astronomical atmosphere axis Bessel Besselian body catalogue celestial celestial pole celestial sphere centre circle coefficients computation constant coordinates correction curvature declination density derived determined developed differences differential earth ecliptic ephemeris epoch equation equatorial equinox expressed factor formulae function fundamental fundamental plane geocentric geoid given gives height horizon hypothesis index of refraction infinitesimal initial epoch integration interpolation kilometres latitude logarithms longitude luni-solar precession mean pole meridian method moon multiplied nutation obliquity observations Observatory parallax plane polar position Poulkova practical preceding precessional motions probable error proper motion quantities R.A. and Dec radius rate of diminution reduction referred right ascension rigorous secular variations sidereal solar speed spherical standard standard gravity stars strata Substituting surface temperature theory triangle values variation zenith distance
Page 392 - B . sin c = sin b . sin C cos a = cos b . cos c + sin b . sin c cos b = cos a . cos c + sin a . sin c cos A cos B cos c = cos a . cos b + sin a . sin b . cos C ..2), cotg b . sin c = cos G.
Page v - The present volume is the first of a projected series having the double purpose of developing the elements of Practical and Theoretical Astronomy for the special student of the subject, and of serving as a handbook of convenient reference for the use of the working astronomer In applying methods and formulae.
Page 223 - There is, perhaps, no branch of practical astronomy on which so much has been written as on this (astronomical refraction) and which is still in so unsatisfactory a state. The difficulties connected with it are both theoretical and practical. The theoretical difficulties arise from the uncertainty and variability of the law of diminution of the density of the atmosphere with height, and also from...
Page 165 - ... the ratio of the velocity of the Earth in its orbit to the velocity of light, might not need correction or modification.
Page 385 - Catalogue of 12,441 stars for the epoch 1880, from observations made at the Royal Observatory, Cape of Good Hope, during the years 1871 to 1879.
Page 250 - The circumstances in these cases are different from those of the earth and moon, in the important respect that the ratio of the mass of the moon to that of the earth is much greater than the ratio of the mass of any other satellite to that of its primary.
Page 385 - First Melbourne General -Catalogue of 1227 stars for the epoch 1870 deduced from observations extending from 1863 to 1870 made at the Melbourne Observatory.
Page v - The most urgent want which the work is intended to supply is that of improved methods of deriving and reducing the positions and proper motions of the fixed stars. Modifications of the older methods are made necessary by the long period through which positions of the stars have to be reduced, and by the extension of astronomical and statistical researches to a great and constantly increasing number of telescopic stars. Especial attention has therefore been given to devising the most expeditious and...
Page 116 - Before the introduction of railways, people used to set their clocks by the sun. But owing to the obliquity of the ecliptic and the eccentricity of the earth's orbit around the sun, the intervals between successive passages of the sun are not exactly equal. The consequence is that, if a clock keeps exact time, the sun will sometimes pass the meridian before and sometimes after twelve by the clock. When this was understood, a distinction was made between apparent...