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Grundyloop t1_ix8p6m4 wrote

We use something called ephimerides, which describe how much an object moves in longitude and latitude (Right Ascension and Declination) per day etc. In other words, they describe the trajectory of a moving celestial object. The vast majority of celestial objects don’t move appreciably on the sky from one year to the next, the exceptions being solar system objects (planets, comets, asteroids) and a handful of nearby stars.

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