sidereal
71sidereal year — noun Date: 1681 the time in which the earth completes one revolution in its orbit around the sun measured with respect to the fixed stars ; 365 days, 6 hours, 9 minutes, and 9.5 seconds of mean time …
72sidereal day — Astron. the interval between two successive passages of the vernal equinox over the meridian, being about four minutes shorter than a mean solar day. [1785 95] * * * …
73sidereal hour angle — Astron. the angle, measured westward through 360°, between the hour circle passing through the vernal equinox and the hour circle of a celestial body. Cf. hour angle. * * * …
74sidereal month — Astron. See under month (def. 5). [1865 70] * * * …
75sidereal year — Astron. year (def. 4c). [1675 85] * * * …
76sidereal time — noun Time measured by the apparent diurnal motion of the vernal equinox; approximated by that based on the rotation of the Earth relative to the stars …
77SIDEREAL YEAR — the period during which the earth makes a revolution in its orbit with respect to the stars …
78sidereal light — light of stars …
79sidereal hour angle — The angle about the celestial pole between the celestial meridian of the first point of Aries and the celestial meridian of the body, measured westward from the celestial meridian of the first point of Aries …
80sidereal day — noun Astronomy the time between consecutive meridional transits of the First Point of Aries, almost four minutes shorter than the solar day …
