ephemeris
ephemeris — noun
1. A chart or list, usually updated every year, that gives the predicted positions
A chart or list, usually updated every year, that gives the predicted positions of planets, stars, and other objects in the sky at specific times. Astronomers, sailors, and space agencies use it to plan observations, navigation, and missions.
Padma checked the ephemeris at the university library to plan her stargazing nights.
ephemeris + purpose clause (to plan)
The annual ephemeris from the observatory lists sunrise and sunset times for each day of the year.
annual ephemeris — yearly publication
Kofi used an online ephemeris to find when Saturn would be visible from his garden.
Without the ship's nautical ephemeris, the captain could not navigate by the stars.
Hassan learned to read the ephemeris in his astronomy class and soon found Mars on his own.
- astronomical table
broader term; any table of astronomical data, not only positions
- celestial calendar
less technical; used by amateur astronomers for planning observations
- star chart
different format — a visual map of the sky, not a numeric table
文法句型
ephemeris + of + [celestial body]
annual/online/nautical ephemeris
用法筆記
The plural form is ephemerides /ˌɛfəˈmɛrədiːz/. Often used with descriptive adjectives (annual, nautical, online) or a possessive noun (the observatory's ephemeris, the ship's ephemeris). The word is primarily found in astronomy, navigation, and space-science contexts.