the angular distance of a point on the celestial sphere from the great circle that is perpendicular to the ecliptic at the point of the vernal equinox, measured through 360° eastward parallel to the ecliptic.
the angular distance measured eastwards from the vernal equinox to the intersection of the ecliptic with the great circle passing through a celestial body and the poles of the ecliptic Also called ecliptic longitude
The position of a celestial object east of the vernal equinox along the ecliptic. Celestial longitude is measured in degrees eastward from the vernal equinox (0°) to the point where a great circle drawn through the object and the poles of the ecliptic intersects the ecliptic. Compare celestial latitude. See more at ecliptic coordinate system.
the branch of astronomy that deals with the application of the laws of dynamics and Newton’s law of gravitation to the motions of heavenly bodies. noun the study of the motion of celestial bodies under the influence of gravitational fields celestial mechanics The science of the motion of celestial bodies under the influence of gravitational […]
- Celestial meridian
celestial meridian A great circle on the celestial sphere passing through the celestial poles and an observer’s zenith. An observer’s celestial meridian is not a fixed reference on the celestial sphere but rather changes with the observer’s location on Earth. Stars transit an observer’s celestial meridian (that is, cross directly overhead in the sky at […]
navigation by means of observations made of the apparent position of heavenly bodies. noun navigation by observation of the positions of the stars Also called astronavigation celestial navigation Navigation of a ship or aircraft based on the observed positions of celestial bodies. See more at altazimuth coordinate system.
each of the two points in which the extended axis of the earth cuts the celestial sphere and about which the stars seem to revolve. noun either of the two points at which the earth’s axis, extended to infinity, would intersect the celestial sphere Sometimes shortened to pole celestial pole Either of the two points […]