octaeteris
Sign in to saveIn astronomy, an octaeteris (, plural: octaeterides) is the period of eight solar years after which the moon phase occurs on the same day of the year plus one or two days.
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Within Vinony's link graph, octaeteris is referenced by 81 other articles, and connects out to orbital period, tropical year and lunar month.
It sits within the topics Ancient Greek astronomy, Calendars and Time in astronomy.
Its subject is documented across 7 Wikipedia language editions.
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In astronomy, an octaeteris (, plural: octaeterides) is the period of eight solar years after which the moon phase occurs on the same day of the year plus one or two days.
This period is also in a very good synchronicity with five Venusian visibility cycles (the Venusian synodic period) and thirteen Venusian revolutions around the Sun (Venusian sidereal period). This means, that if Venus is visible beside the Moon, after eight years the two will be again close together near the same date of the calendar. {| class="wikitable" |+ Comparison of differing parts of the octaeteris ! Astronomical period ! Number in anoctaeteris ! Overall duration(Earth days) |- | Tropical year |align=right| 8     | 2 921.93754 |- | Synodic lunar month |align=right| 99     | 2 923.528230 |- | Sidereal lunar month |align=right| 107     | 2 923.417787 |- | Venusian synodic period |align=right| 5     | 2 919.6 |- | Venusian sidereal period |align=right| 13     | 2 921.07595 |}
Excerpted from Wikipedia’s “octaeteris” article, available under the CC BY-SA 4.0 licence.