| 释义 |
DictionarySeeephemeris timeephemeris second
ephemeris second See ephemeris time.ephemeris second[ə′fem·ə·rəs ′sek·ənd] (astronomy) The fundamental unit of time of the International System of Units from 1960 until 1968, equal to 1/31556925.9747 of the tropical year defined by the mean motion of the sun in longitude at the epoch 1900 January 0 day 12 hours. |