Lunisolar calendar — A lunisolar calendar is a calendar in many cultures whose date indicates both the moon phase and the time of the solar year. If the solar year is defined as a tropical year then a lunisolar calendar will give an indication of the season; if it is … Wikipedia
Precession (astronomy) — In astronomy, precession refers to the movement of the rotational axis of a body, such as a planet, with respect to inertial space. In particular, it refers to the precession of the Earth s rotational axis, also called the precession of the… … Wikipedia
Acoreus — was a wise man consulted by Julius Caesar, according to the Roman writer Lucan, asking him many questions about ancient Egypt’s history and its calendar. Caesar learned that the Egyptians based their year on the solar year, that is, on the… … Wikipedia
Meton of Athens — (Greek: Μέτων ὁ Ἀθηναῖος; gen.: Μέτωνος) was a Greek mathematician, astronomer, geometer, and engineer who lived in Athens in the 5th century BC. He is best known for calculations involving the eponymous 19 year Metonic cycle which he introduced… … Wikipedia