Lessons in Astronomy: Including Uranography. A Brief Introductory Course Without MathematicsGinn, 1893 - 357 стор. |
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Загальні терміни та фрази
Algol Alpha altitude Andromeda angle apparent diameter asteroids astronomical astronomical units Auriga axis Beta Boötes bright lines bright stars called Cassiopeia celestial equator celestial sphere centre circle comet conspicuous constellation dark lines Delta density determined disc distance diurnal double star earth earth's orbit eclipse Epsilon equatorial equinox Gamma globe heat heavenly bodies heavens horizon inches inferior conjunction instrument Jupiter known latitude length less light longitude lunar magnitude Mars mass mean meridian meteors miles minutes month moon moon's motion move naked eye nearly nebulæ Neptune object object-glass observer Orion parallax perihelion period photosphere planet planetary pole Pole-star probably proper motion right ascension ring rotation satellites seen shadow sidereal sidereal period Sirius solar system spectra spectroscope spectrum sun spots sun's synodic synodic period tail tide tion Uranus Ursa velocity Venus vernal equinox visible zenith Zeta zodiacal
Популярні уривки
Сторінка 159 - The squares of the periods of revolution of any two planets are proportional to the cubes of their mean distances from the sun.
Сторінка 160 - that every particle of matter in the universe attracts every other particle, with a force whose direction is that of the line joining the two, and whose magnitude is directly as the product of their masses, and inversely as the square of their distances from each other.
Сторінка 171 - Mercury will be represented by a grain of mustard seed, on the circumference of a circle 164 feet in diameter for its orbit; Venus a pea, on a circle 284 feet in diameter; the Earth also a pea, on a circle of 430 feet; Mars a rather large pin's head, on a circle of 654 feet...
Сторінка 204 - Direct your telescope to a point on the ecliptic in the constellation of Aquarius, in longitude 826°, and you will find within a degree of that place a new planet, looking like a star of about the ninth magnitude, and having a perceptible disc.
Сторінка 11 - Equinoctial, is the great circle in which the plane of the earth's equator produced intersects the surface of the celestial sphere.
Сторінка 171 - Venus a pea, on a circle of 284 feet in diameter ; the Earth also a pea, on a circle of 430 feet ; Mars a rather large pin's head, on a circle of 654 feet ; the Asteroids, grains of sand, in orbits of from 1000 to 1200 feet; Jupiter a moderate-sized orange, in a circle nearly half a mile across...
Сторінка 79 - ... prehistoric times, and have received fanciful names. Sometimes the arrangement of the stars bears a resemblance to the object after which the constellation is named; in general, however, no reason can be given for the way in which the stars have been grouped and named.
Сторінка 75 - ... is more distant at the former than at the latter. The diminished force of gravity at the equator has, it is true, another cause, namely, the centrifugal force arising from the rotation of the E..
Сторінка 52 - ... animal's neck, and reaches Theta in his ear. Epsilon (or Enif), the bright star 8° northwest of Theta, marks his nose. The forelegs are in the northwestern part of the constellation just east of Cygnus, and are marked, one of them by the stars Eta and Pi, and the other by Iota and Kappa. This is the winged horse which sprang from the blood of Medusa, after Perseus had cut off her head. He fixed his residence on Mt. Helicon, where he was the favorite of the Muses, and after being tamed by Minerva...
Сторінка 319 - SA. The whole apparent retardation of the eclipses between opposition and conjunction, should therefore be exactly twice the time required for light to come from the sun to the earth. This time is very nearly 500 seconds, or 8m 20'.