Elements of Astronomy ...: With Explanatory Notes, and Questions for ExaminationFarmer, Brace & Company, 1855 - 321 σελίδες |
Άλλες εκδόσεις - Προβολή όλων
Συχνά εμφανιζόμενοι όροι και φράσεις
altitude angular aphelion apogee apparent diameter apparent motion appear apsides ascertained asteroid astronomers atmosphere axis celestial equator celestial sphere centre changes circle circumference comet constellation craters degrees Describe difference direction discovered disk earth earth's orbit equal Explain from figure extent fixed stars globe Grammar heavenly body heavens hemisphere horizon hundred illumined inclination inferior conjunction J. R. Hind Jupiter latitude latter length libration longitude lunar eclipse magnitude Mars mean solar measured Mercury meridian miles moon moon's orbit mountains move nearly nebula nodes observations occur parallax passing penumbra perigee perihelion period planet position precession Prof quarter radius rays refraction respecting revolution revolve right angle right ascension ring rotation satellites Saturn seen shadow sidereal sidereal day solar day solar distance solar eclipse space spectator spots sun's surface synodical month tance telescope tides tion triangle velocity Venus vernal equinox visible west to east zenith
Δημοφιλή αποσπάσματα
Σελίδα 296 - The fourth term is found by multiplying the second and third terms together and dividing by the first § 14O.
Σελίδα 24 - A sphere is a solid bounded by a curved surface, every point of which is equally distant from a point within called the center.
Σελίδα 164 - These phenomena do not, however, occur at every new and full moon ; and the reason is, that the plane of the moon's orbit is inclined to that of the ecliptic, and that these two planes' meet one another only in their line of common section, which passes through the centre of the earth.
Σελίδα 305 - On a careful re-examination of the heavens, too, and a comparison of catalogues, many stars are now found to be missing-; and although there is no doubt that these losses have often arisen from mistaken entries, yet in many instances it is equally certain that there is no mistake in the observation or entry, and that the star has really been observed, and as really has disappeared from the heavens...
Σελίδα 24 - A SPHERE is a solid bounded by a curved surface, every part of which is equally distant from a point within, called the centre.
Σελίδα 162 - In some of the principal ones, decisive marks of volcanic stratification, arising from successive deposits of ejected matter, and evident indications of Lava currents streaming outwards in all directions, may be clearly traced with powerful telescopes.
Σελίδα 13 - Dodd, I find it greatly superior to all others which have come under my notice, in system, completeness, and nomenclature. The arrangement is natural, the system complete, and the nomenclature greatly improved. These improvements are not slight; they are fundamental— eminently worthy the attention of the mathematical teacher, and give a character of unity to the work which at once distinguishes it from all others on this subject.
Σελίδα 50 - ... the sun. More Accurate Computations. — A more accurate determination of the phases as visible at any point of the earth's surface may be obtained from the Besselian elements which are given for every ten minutes of Greenwich mean time. Their geometric signification is as follows: — Let us imagine a plane passing through the centre of the earth, perpendicular to the right line joining the centres of the sun and moon. This latter line is the axis of the moon's shadow, and the plane is called...
Σελίδα 51 - Circles are great circles passing through the zenith of an observer, and perpendicular to his horizon. The vertical circle passing through the east and west points of the horizon is called the Prime Vertical ¡ that passing through the north and south points coincides with the celestial meridian.
Σελίδα 318 - This is an irresolvable nebula, figured by Sir John Herschel, during his residence at the Cape of Good Hope. Its favourable position, as seen in southern latitudes, enabled Herschel to trace the outline of the nebula much farther than any preceding observer had done. The singular figure of this object seems to suggest some power of attraction operating on the particles of matter, or the...