The Observatory, Volume 7Editors of the Observatory, 1884 Some vols. for 1886- include a special issue: Annual companion to the Observatory. |
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Common terms and phrases
aperture appeared April Astronomer Royal Astronomical Society axis belt bright Cape catalogue colour comet comparison corona dark determination diameter disk distance double stars eclipse Ephemeris equator equatoreal errors faculæ faint Father Perry Geminorum Gill Greenwich Greenwich Mean heliometer Herschel inches instrument July June Jupiter Knobel light limb longitude lunar Lyræ magnitude maximum mean solar measures meridian meteors micrometer minimum Minor Planet Monocerotis Moon Moon's Neptune object object-glass observations obtained occultations orbit paper parallax period photographs photometric planet position position-angles present Prof Professor proper motions Ranyard red spot remarkable Right Ascension ring rotation Royal Observatory Sagittarii satellite Saturn seen Sept sidereal spectroscope spectrum stellar sun-spots Sun's surface tables telescope theory tion transit Transit of Venus Trouvelot Tupman Uranometria Uranus Variable Stars veiled spots Venus Virginis visible ΙΟ
Popular passages
Page 318 - Its satellite system also deserves careful observation, especially in respect to the eclipses which occur; since we find in them a measure of the time required for light to cross the orbit of the Earth, and so of the solar parallax, and also because, as has been already mentioned, they furnish a test of the constancy of the Earth's rotation. The photometric method of observing these eclipses, first instituted by Professor PICKERING at Cambridge in 1878, and since re-invented by COBNU in Paris, has...
Page 202 - There is no change of importance to notice in this instrument, which has been kept in good working order. A reversion-prism for use with the collimators as well as with the transit-circle is being made by Messrs. Troughton and Simms. The sun, moon, planets, and fundamental stars have been regularly observed throughout the year, together with other stars from a working catalogue of 2600 stars, comprising all stars down to the sixth magnitude inclusive which have not been observed since 1860. Considerable...
Page 277 - Cape of Good Hope, is doubtful; not to the extent of only a few hundred feet, as commonly supposed, but the uncertainty amounts to some thousands of feet, and may possibly be a mile or more, probably not less than a ten-thousandth of the whole distance; and the direction of the line is uncertain in about the same degree. Of course, on those portions of either continent which have been directly connected with each other by geodetic triangulations, no corresponding uncertainty obtains ; and as time...
Page 318 - It seems quite certain that no analogies drawn from the earth and the earth's atmosphere alone will explain the strange things seen upon his disk, some of which, especially the anomalous differences observed between the rotation periods derived from the observation of markings in different latitudes, are very similar to what we find upon the sun. 'The great red spot...
Page 283 - ... be preserved for future comparison as unimpeachable witnesses. I will not leave the moon without a word in respect to the remarkable speculations of Professor George Darwin concerning the tidal evolution of our satellite. Without necessarily admitting all the numerical results as to her age and her past and future history, one may certainly say that he has given a most plausible and satisfactory explanation of the manner in which the present state of things might have come about through the operation...
Page 281 - Asia and America the effects would be trifling. The only observational evidence of such movements of the pole, which thus far amounts to anything, is found in the results obtained by Nyren in reducing the determinations of the latitude of Pulkowa, made with the great vertical circle, during the last twentyfive years. They seem to show a slow, steady diminution of the latitude of this observatory, amounting to about a second in a century ; as if the north pole were drifting away, and increasing its...
Page 348 - For sale by all Booksellers. Sent by mail, post-paid, on receipt of price by the Publishers, HOUGHTON, MIFFLIN & CO., BOSTON, MASS. I...
Page 145 - Moon by means of observations of the positions of a crater near the center of the lunar surface. 3. "The effect of irradiation and its variations on the apparent semidiameter of the Moon. 4. "The systematic variation of the apparent place produced by the irregularities on its limb. 5. " The real libration of the Moon by a method independent of the errors caused by abnormal variations in the apparent semi-diameter of the Moan.
Page 320 - ... of solution. Thus, while experiments upon the velocity of light and heliometric measurements of the displacements of Mars among the stars agree remarkably in assigning a smaller parallax (and greater distance of the sun) than seems to be indicated by the observations of the late transits of Venus, and by methods founded on the lunar motions, on the other hand, the meridian observations of Mars all point to a larger parallax and smaller distance. While still disposed to put more confidence in...
Page 365 - Newton, and others, who consider them to be strangers coming in from outer space, sometimes ' captured ' by planets, and forced into elliptic orbits, so as to become periodic in their motion. Certainly this theory has strong supports and great authority, and probably it meets the conditions better than any other yet proposed. But the objections are really great, if not insuperable, — the fact that we have so few, if any, comets moving in hyperbolic orbits, as comets met by the sun would be expected...