Astronomy |
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Common terms and phrases
61 Cygni aberration of light accurate actually angle angular distance annual motion apparent diurnal motion apparent motion astronomical attraction axis of collimation binary star called celestial sphere centre circular colatitude consequently consider constellation culmination declination describe determined diameter direction diurnal motion double star Dunsink earth ecliptic ellipse equal equator exceedingly explained fixed stars follows globe Greenwich heavens hemisphere hence horizon interval Jupiter Kepler's kilometres known latitude length magnitude mean noon mean sun measure Mercury meridian circle minute moon nearly nebulæ objects observations orbit parallax parallel passes pegtop perpendicular pivots planet Pleiades polar axis polar distance Pole Star present proper motion radius rays refraction remarkable revolution right ascension rotation round the sun satellites seen sidereal clock sidereal day Sirius subtends sun's supposition surface tance tele tion transit instrument triangle unaided eye velocity of light Venus vernal equinox visible wire zenith distance
Popular passages
Page 124 - It would be a vain task to attempt to count the stars in one of these globular clusters. They are not to be reckoned by hundreds ; and on a rough calculation, grounded on the apparent intervals between them at the borders...
Page 45 - ... would, therefore, were it not for the atmosphere, be invisible. The time of apparent sunrise and sunset is what is now given in our almanacs.
Page vii - The works comprised in the SERIES will all be composed with special reference to their use in school-teaching; but, at the same time, particular attention will be given to making the information contained in them trustworthy and accurate, and to presenting it in such a way that it may serve as a basis for more advanced study. In conformity with the special object of the Series, the attempt will be made in all cases to bring out the educational value which properly belongs to the study of any branch...
Page i - SERIES, the attempt will he made in all cases to bring out the educational value which properly belongs to the study of any branch of Science, by not merely treating of its acquired results, but by explaining as fully as possible the nature of the methods of inquiry and reasoning by which these results have been obtained. Consequently, although the treatment of each subject will be strictly elementary, the fundamental facts will be stated and discussed with the fulness needed to place their scientific...
Page 73 - In the motion of a planet round the sun, the radius vector, drawn from the centre of the sun to the planet, sweeps over equal areas in equal times.
Page 143 - Resolvable nebulae, or such as excite a suspicion that they consist of stars, and which any increase of the optical power of the telescope may be expected to resolve into distinct stars; 3d...
Page 67 - We know now that this apparent variation in the motion of the planets is simply due to the annual motion of the earth in its orbit round the sun.
Page 144 - It is small and particularly well defined, so as to have more the appearance of a flat oval solid ring than of a nebula. The axes of the ellipse are to each other in the proportion of about 4 to 5, and the opening occupies about half or rather more than half the diameter. The central vacuity is not quite dark, but is filled in with faint nebula, like a gauze stretched over a hoop.
Page i - NOTWITHSTANDING the large number of scientific works which have been published within the last few years, it is very generally acknowledged by those who are practically engaged in Education, whether as Teachers or as Examiners, that there is still a want of Books adapted for school purposes upon several important branches of Science.
Page 78 - T be the initial position of the planet. If the planet be simply released, it will immediately begin to fall along the line TS into the sun. If, on the other hand, the planet were initially projected along the line TZ perpendicular to...