Elements of Astronomy Designed for Academics and High SchoolsHarper & Bros., 1897 - 254 pages |
Other editions - View all
The Elements of Astronomy: Designed for Academies and High Schools Elias Loomis No preview available - 2018 |
The Elements of Astronomy: Designed for Academies and High Schools Elias Loomis No preview available - 2015 |
Common terms and phrases
aerolites altitude angle aphelion apparent diameter apparent motion appear asteroids astronomers atmosphere attraction axis binary stars brass meridian bright called celestial celestial equator centre circle comet computed conjunction constellation dark degrees density determined direction diurnal diurnal motion earth earth's surface eccentricity ecliptic entire equal equator fixed stars globe greater greatest elongation heavens height Hence horizon inferior conjunction inferior planet interval Jupiter latitude length less light luminous lunar magnitude Mars mass mean distance Mercury meteors miles per second millions of miles moon moon's move naked eye nearly nucleus observed opposite orbit parallax particles perihelion period pole portion position proper motion radius revolution revolve right ascension ring rotation satellite Saturn seen shadow shooting stars sidereal sometimes spots sun's disc sun's place superior conjunction superior planet supposed synodic period tail telescope tide tion transit twilight Uranus velocity Venus vernal equinox visible zenith
Popular passages
Page 55 - According to a law of optics, when a ray of light passes obliquely from a rarer to a denser medium, it is bent toward the perpendicular to the refracting surface.
Page 217 - The names of the signs of the zodiac are: Aries, Taurus, Gemini, Cancer, Leo, Virgo, Libra, Scorpio, Sagittarius, Capricornus, Aquarius, and Pisces.
Page 40 - A particular place, and the hour of the day at that place being given, to find what hour it is at any other place. RULE. Bring the place at which the time is given to the brass meridian, and set the index...
Page 44 - When the instrument has been adjusted, the middle wire mm' will be in the plane of the meridian, and when an object is seen upon it, such object will be on the celestial meridian, and the wire itself may be regarded as a small arc of the meridian rendered visible. The...
Page 83 - Elevate the pole as many degrees above the horizon as are equal to the latitude of the place, and screw the quadrant of altitude on the brass meridian, over that latitude; bring the sun's place in the ecliptic to the brass meridian, and set the index of the...
Page 179 - J and s' j', their shadows are projected on the surface of the planet in the same manner as the shadow of the moon is projected on the earth in a solar eclipse, and in this case the shadow may be seen moving across the disk of the planet, in a direction parallel to its belts, as a small round and intensely black spot. 2954. 3rd. Occupations of the satellites by the planet. — When a satellite, passing behind the planet, is between the tangents EJ a...
Page 71 - In this case, it is obvious that the plane of the circle of illumination would be perpendicular to a line drawn from the centre of the sun to the centre of the earth...
Page 11 - The same observations prove that this movement of rotation of all the stars is perfectly uniform. 6. Time of one Revolution of the Celestial Sphere. — If the telescope be detached from the clock-work, and, having been pointed upon a star, be left fixed in its position, and the exact time of the star's passing the central wire be noted, on the next night, at about the same hour, the star will again arrive upon the central wire. The time elapsed between these two observations will be found to be...
Page 229 - IN 1803, Sir William Herschel first determined and announced to the world, that there exist among the stars separate systems, composed of two stars revolving about each other in regular orbits. These he denominated binary stars, to distinguish them from other double stars where no such motion is detected, and whose proximity to each other may possibly arise from casual juxtaposition, or from one being in the range of the other.
Page 179 - JVJ' its conical shadow; SS' the sun ; E and E" the positions of the earth when the planet is in quadrature. Let ADFK represent the orbit of one of the satellites, whose plane we will suppose to coincide with the ecliptic. From E draw the lines EJ, EJ', meeting the path of the satellite at H and K, as also at C and D. Let A and B be the points where the path' of the satellite crosses the limits of the shadow. By a computation similar to that employed in the case of the earth, Art. 286, we find that...