the.com/ephemeris

A calendar for things that never agreed to our calendars in the first place.

means A table that charts the predicted positions of a celestial body — planet, moon, comet, satellite — at regular intervals over time.

from From Greek ephēmeris, meaning 'diary' or 'daybook' — literally 'lasting a day,' from epi- ('on') plus hēmera ('day'). The Greeks and later astrologers used the word for any day-by-day record, but it narrowed over centuries to mean specifically the daily record of where a planet sits in the sky — a diary kept not by a person, but on one, for the heavens.

origin
from greek word for diary, daily record
used by
astronomers, astrologers, and sailors before gps
core idea
predicts exact positions of planets over time
navigation role
let sailors find longitude from star positions
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