Plane astronomy |
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Common terms and phrases
accurately angular distance antarctic circle apparent direction appear astronomical axis azimuth bisects called celestial equator celestial sphere clock coincide conjunction consequently correction curve declination described determined diameter diurnal motion Earth Earth's centre Earth's orbit Earth's surface eclipse enlightened hemisphere equal equinox error exactly field of view fixed stars greatest heavenly bodies Hence horizon-glass inclination index-glass inferior planet instrument intersection latitude limb line of collimation line of graduation line of nodes longitude lunar lunar eclipses means measured meridian altitude Moon motion mural circle nearly object-glass observed angle opposite parallax parallel passed the meridian perigee perpendicular phenomena plane pole position radius reflected image refraction revolution revolves right angle right ascension sea-line seen sextant shadow shewn sidereal sidereal day Sidereal period solar solstice space sphere of observation spherical straight line subtended Sun's supposing Synodic period tangent telescope transit true direction velocity vernier wire zenith distance zero
Popular passages
Page 6 - A sphere is a surface every point of which is equally distant from a point within it,
Page 6 - (1). Every section of a sphere made by a plane is a circle. Let
Page 14 - between the tropic of Cancer and the arctic circle, and between the tropic of Capricorn and the antarctic circle, are called respectively the
Page 3 - varies directly as the mass of the attracting body and inversely as the square of its distance from the attracted body.
Page 23 - the altitude of the pole above the horizon is equal to the latitude of the place. The
Page 2 - planet is attracted to the sun by a force varying inversely as the square of the distance from the sun.
Page 7 - When the cutting plane passes through the centre of the sphere, the section is called a great circle.
Page 7 - The diameter of the sphere which is perpendicular to the plane of any
Page 7 - of the Earth is inclined to the plane of the orbit at an angle of about 66°
Page 69 - passes through the centre of the horizon-glass, meeting its surface at the same angle as the line drawn from the same point to the centre of the index-glass. Hence a ray of light reflected from the centre of the index-glass to that of the horizon-glass is again reflected along the line of collimation of the telescope.