Block, SkipCaptcha, Upload, Automoderated users, edit
14,282
edits
Changes
Jump to navigation
Jump to search
Line 32:
Line 32: − + + +
→Alignment
Sosigenes aligned the calendar so that the spring equinox would fall on March 25. He used observations of the equinox found in a work by Hipparchus, a standard astronomy reference work of this time. The observations are thought to have been made around 135 BC in Alexandria.
Sosigenes aligned the calendar so that the spring equinox would fall on March 25. He used observations of the equinox found in a work by Hipparchus, a standard astronomy reference work of this time. The observations are thought to have been made around 135 BC in Alexandria.
In the time of Hipparchus, the equinox occurred when the Sun entered the constellation Aries, or "first point of Aries." The star signs in astrology are also based on the observations of Hipparchus. In modern times, the Sun rises in Pisces on the day of the equinox due to [[precession of equinoxes]]. Although Hipparchus's work has been lost, it is quoted by Ptolemy in ''Almagest''. The Julian calendar drifts by one day every 138 years. In 8 BC, Augustus removed one day from the month February and added it to August, putting the calendar an additional day out of alignment. At the time of the Council of Nicene in 335, the equinox occurred on March 21.<ref>(335+135)/138 gives us 3.4 days of calendar drift, plus one day for Augustus's reform.</ref> The Gregorian calendar reestablished the alignment at the time of Nicene.
In the time of Hipparchus, the equinox occurred when the Sun entered the constellation Aries, or "first point of Aries." The star signs in astrology are also based on the observations of Hipparchus. In modern times, the Sun rises in Pisces on the day of the equinox due to [[precession of equinoxes]]. Although Hipparchus's work has been lost, it is quoted by Ptolemy in ''Almagest''.
The Julian calendar drifts by one day every 138 years. In 8 BC, Augustus removed one day from the month February and added it to August, putting the calendar an additional day out of alignment. At the time of the Council of Nicene in 335, the equinox occurred on March 21.<ref>(335+135)/138 gives us 3.4 days of calendar drift, plus one day for Augustus's reform.</ref> The Gregorian calendar reestablished the alignment at the time of Nicene.
== Later history ==
== Later history ==