Lessons in Astronomy, Including Uranography: A Brief Introductory Course Without MathematicsGinn & Company, 1903 - 420 стор. |
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Загальні терміни та фрази
Algol Alpha altitude Andromeda angle apparent diameter asteroids astronomical astronomical units atmosphere axis Beta Boötes bright lines Cassiopeia celestial equator celestial sphere circle clouds comet conspicuous constellation dark lines Delta density determined disk diurnal double star earth earth's orbit east eclipse Epsilon equatorial equinox Gamma globe heat heavenly bodies heavens horizon inferior conjunction instrument Jupiter known latitude length less light longitude lunar magnitude Mars mass meridian meridian circle meteors miles a second moon moon's motion move naked eye nearly nebula Neptune object object-glass Observatory observer parallax perihelion period photographs photosphere planet planetary pole Pole-star probably proper motion right ascension ring rotation satellites Saturn seen shadow sidereal sidereal period Sirius small telescope solar system spectra spectroscope spectrum spots sun-spots tail temperature tion URANOGRAPHY Uranus Ursa usually variable velocity Venus vernal equinox visible zenith Zeta zodiacal
Популярні уривки
Сторінка 188 - The squares of the periods of the planets are proportional to the cubes of their mean distances from the sun ; that is, ti2 : k2 ,• ,• ai3 ,• (h3This is the so-called harmonic law.
Сторінка 189 - 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 6 - ... divided into 360 degrees, each degree into 60 minutes, and each minute into 60 seconds.
Сторінка 246 - Direct your telescope to a point on the ecliptic in the constellation of Aquarius, in longitude 326°, 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 202 - On it place a globe, two feet in diameter; this will represent the Sun; 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; Juno, Ceres, Vesta, and Pallas, grains of sand, in orbits of from 1000 to 1200 feet; Jupiter a moderate-sized orange...
Сторінка 243 - sweeping " for interesting objects with a seven-inch reflector of his own construction. He recognized it at once by its disc as something different from a star, but supposed it to be a peculiar sort of a comet, and its planetary character was not demonstrated until nearly a year had passed. It is easily visible to a good eye as a star of the sixth magnitude. Its mean distance from the sun is about 19 times that of the earth, or about 1800,000000 miles, and the eccentricity of its orbit is about...
Сторінка 84 - ... 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 89 - It is taken of that particular width simply because the moon and the principal planets always keep within it. It is divided into the so-called Signs...
Сторінка 58 - 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 he was given to Bellerophon to aid him in conquering the Chimaera.
Сторінка 162 - The heat-unit most used at present is the " calory," l which is the quantity of heat required to raise the temperature of one kilogram of water 1° C. ; and as the result of the best observations thus far made (Langley's) it appears that the " Solar Constant " is approximately thirty of these calories to a square metre in a minute.