sidereal
21sidereal day — n. the time between two successive passages of the vernal equinox across the meridian: it measures one rotation of the earth and equals 23 hours, 56 minutes, 4.1 seconds of mean solar time …
22sidereal month — n. the time required for the moon to complete one revolution around the earth with respect to a fixed star: its average value is 27.32 days of mean solar time …
23sidereal year — n. see YEAR (sense 3) …
24Sidereal year — The sidereal year is the time taken for the Sun to return to the same position with respect to the stars of the celestial sphere. It is the orbital period of Earth, equal to 365.25636042 mean solar days (31,558,149.540 seconds), that is… …
25sidereal day — a unit of time used in astronomy, equal to the period of time in which the earth makes one rotation relative to the stars. If we could view the earth from outside the Solar System, we would see that it actually completes 366.242 rotations… …
26sidereal time — Astron. time measured by the diurnal motion of stars. A sidereal day is about four minutes shorter than a solar day, with hours, minutes, and seconds all proportionally shorter. [1805 15] * * * ▪ astronomy time as measured by the apparent… …
27Sidereal day — Day Day (d[=a]), n. [OE. day, dai, dei, AS. d[ae]g; akin to OS., D., Dan., & Sw. dag, G. tag, Icel. dagr, Goth. dags; cf. Skr. dah (for dhagh ?) to burn. [root]69. Cf. {Dawn}.] 1. The time of light, or interval between one night and the next; the …
28sidereal day — Day Day (d[=a]), n. [OE. day, dai, dei, AS. d[ae]g; akin to OS., D., Dan., & Sw. dag, G. tag, Icel. dagr, Goth. dags; cf. Skr. dah (for dhagh ?) to burn. [root]69. Cf. {Dawn}.] 1. The time of light, or interval between one night and the next; the …
29sidereal period — Time required for a celestial body in the solar system to complete one revolution with respect to the fixed stars (as observed from a fixed point outside the system). A planet s sidereal period can be calculated from its synodic period. The… …
30sidereal time — noun measured by the diurnal motion of stars • Hypernyms: ↑cosmic time • Hyponyms: ↑sidereal day, ↑day, ↑sidereal year, ↑sidereal hour, ↑sidereal month …
