An Elementary Treatise on Astronomy: In Four Parts. Containing a Systematic and Comprehensive Exposition of the Theory, and the More Important Practical Problems; with Solar, Lunar, and Other Astronomical Tables. Designed for Use as a Text-book in Colleges and AcademiesJ. Wiley, 1853 - 382 pages |
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Common terms and phrases
aberration altitude angle angular anomaly apparent distance apparent latitude apparent longitude argument ascension and declination astronomical axis calculation called centre circle circle of latitude comet computed Diff difference direction disc double stars earth eclipse epoch equa equal equation equinox Evection fixed stars formula given gravity greater greatest obscuration Greenwich heavens Herschel horizon horizontal parallax hourly motion interval John Herschel limb longitude and latitude lunar mean anomaly mean longitude meridian moon motion in longitude nearly nebulous node Nutation obliquity observed obtained orbit parallax perigee perihelion period perpendicular planet pole position quantity radius-vector refraction retrograde motion revolution right ascension rotation satellites seen semi-diameter shadow sidereal solar solstice subtract sun and moon sun's longitude supposed syzigies Table tail tang telescope tion true true anomaly true longitude tude Uranus variation velocity Venus vernal equinox zenith distance
Popular passages
Page 82 - The squares of the periods of revolution of any two planets are proportional to the cubes of their mean distances from the sun.
Page 380 - Way, and clustering groups sufficiently insulated and condensed to come under the designation of irregular, and in some cases pretty rich clusters. But besides those, there are also nebulae in abundance, both regular and irregular; globular clusters in every state of condensation; and objects of a nebulous character quite peculiar, and which have no analogue in any other region of the heavens.
Page 380 - ... we could plainly see that all about the trapezium is a mass of stars ; the rest of the nebula also abounding with stars and exhibiting the characteristics of resolvability strongly marked.
Page 381 - Throughout by far the larger portion of the extent of the Milk-y Way in both hemispheres, the general blackness of the ground of the heavens on which its stars are projected, and the absence of that innumerable multitude and excessive crowding of the smallest visible magnitudes, and of glare produced by the aggregate light of multitudes too small to affect the eye singly, which the contrary supposition would appear to necessitate, must, we think, be considered unequivocal indications that its dimensions...
Page 20 - LONGITUDE of a place, in geography, is an arch of the equator, intercepted between the first meridian and the meridian passing through the...
Page 382 - ... our view is limited by this sort of cosmical veil, which extinguishes the smaller magnitudes, cuts off the nebulous light of distant masses, and closes our view in impenetrable darkness; while at another we are compelled, by the clearest evidence telescopes can afford, to believe that star-strewn vistas lie...
Page 30 - ... or 7% 7, &c. according to its apparent relative distance from the wire. This kind of observation must be made at each of the five wires, and a mean of the whole taken, which will represent the time of the star's passage over the mean or meridional wire. The utility of having five wires instead of the central one only, will be readily understood, from the consideration that a mean result of several observations is deserving of more confidence than a single one ; since the chances are, that an...
Page 380 - J per square degree, which very far exceeds the average of any other, even the most crowded parts of the nebulous heavens. In the nubecula...
Page 161 - Andes, but they are much less in extent, and do not form a very prominent feature of the lunar surface. Some of them appear very rugged and precipitous, and the highest ranges are, in some places, above four miles in perpendicular altitude. In some instances they...
Page 374 - P', from the orbit of the planet ; which I shall call the diameter of the sphere of the planet's attraction...