REFRACTION n.
ent provided with a graduated circle for the measurement of refraction. -- Refraction of latitude, longitude, declination, right ascension, etc., the change in the apparent latitude, longitude, etc., of a heavenly body, due to the effect of atmospheric refraction. -- Terrestrial refraction, the change in the apparent…
RIGHT a.
ight sailing (Naut.), sailing on one of the four cardinal points, so as to alter a ship's latitude or its longitude, but not both. Ham. Nav. Encyc. -- Right sphere (Astron. & Geol.), a sphere in such a position that the equator cuts the horizon at right angles; in spherical projections, that position of the sphere in…
SEXTANT n.
or measuring angular distances between objects, -- used esp. at sea, for ascertaining the latitude and longitude. It is constructed on the same optical principle as Hadley's quadrant, but usually of metal, with a nicer graduation, telescopic sight, and its arc the sixth, and sometimes the third, part of a circle. See Q…
SPHERE n.
f the sphere, and the problems connected with them, in astronomy and geography, as to the latitudes and longitudes, distance and bearing, of places on the earth, and the right ascension and declination, altitude and azimuth, rising and setting, etc., of the heavenly bodies; spherical geometry. -- Music of the spheres.…
ZENITH n.
or, 3. -- Zenith telescope (Geodesy), a telescope specially designed for determining the latitude by means of any two stars which pass the meridian about the same time, and at nearly equal distances from the zenith, but on opposite sides of it. It turns both on a vertical and a horizontal axis, is provided with a grad…