Octaeteris
Encyclopedia
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 Venus
ian 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
.
The Octaeteris, also known as Oktaeteris, was noted by Cleostratus
in ancient Greece
as a 2923.5 day cycle. The 8 year short lunisolar cycle was probably known to many ancient cultures. The mathematical proportions of the Octaeteris cycles were noted in Classic Vernal rock art in northeastern Utah
by J. Q. Jacobs in 1990. The Three Kings panel also contains more accurate ratios, ratios related to other planets, and apparent astronomic symbolism.
Astronomy
Astronomy is a natural science that deals with the study of celestial objects and phenomena that originate outside the atmosphere of Earth...
, 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 Venus
Venus
Venus is the second planet from the Sun, orbiting it every 224.7 Earth days. The planet is named after Venus, the Roman goddess of love and beauty. After the Moon, it is the brightest natural object in the night sky, reaching an apparent magnitude of −4.6, bright enough to cast shadows...
ian visibility cycles (the Venusian synodic period) and thirteen Venusian revolutions around the sun (Venusian sidereal period). This means, that if Venus
Venus
Venus is the second planet from the Sun, orbiting it every 224.7 Earth days. The planet is named after Venus, the Roman goddess of love and beauty. After the Moon, it is the brightest natural object in the night sky, reaching an apparent magnitude of −4.6, bright enough to cast shadows...
is visible beside the moon
Moon
The Moon is Earth's only known natural satellite,There are a number of near-Earth asteroids including 3753 Cruithne that are co-orbital with Earth: their orbits bring them close to Earth for periods of time but then alter in the long term . These are quasi-satellites and not true moons. For more...
, after eight years the two will be again close together near the same date of the calendar
Calendar
A calendar is a system of organizing days for social, religious, commercial, or administrative purposes. This is done by giving names to periods of time, typically days, weeks, months, and years. The name given to each day is known as a date. Periods in a calendar are usually, though not...
.
| Astronomical period | Number in an Octaeteris | Overall duration (Earth Earth Earth is the third planet from the Sun, and the densest and fifth-largest of the eight planets in the Solar System. It is also the largest of the Solar System's four terrestrial planets... days) |
| Tropical year Tropical year A tropical year , for general purposes, is the length of time that the Sun takes to return to the same position in the cycle of seasons, as seen from Earth; for example, the time from vernal equinox to vernal equinox, or from summer solstice to summer solstice... |
8 | 2921.93754 |
| Synodic lunar month | 99 | 2923.528230 |
| Sidereal lunar month | 107 | 2923.417787 |
| Venus Venus Venus is the second planet from the Sun, orbiting it every 224.7 Earth days. The planet is named after Venus, the Roman goddess of love and beauty. After the Moon, it is the brightest natural object in the night sky, reaching an apparent magnitude of −4.6, bright enough to cast shadows... ian synodic period |
5 | 2919.6 |
| Venusian sidereal period | 13 | 2921.07595 |
The Octaeteris, also known as Oktaeteris, was noted by Cleostratus
Cleostratus
Cleostratus was an astronomer of ancient Greece. He was a native of Tenedos, and the Chaldean astronomer Naburimannu may have been a contemporary of him. He is believed by some scholars to have introduced the zodiac and the solar calendar to Greece from Babylonia. Censorinus Cleostratus (ca....
in ancient Greece
Ancient Greece
Ancient Greece is a civilization belonging to a period of Greek history that lasted from the Archaic period of the 8th to 6th centuries BC to the end of antiquity. Immediately following this period was the beginning of the Early Middle Ages and the Byzantine era. Included in Ancient Greece is the...
as a 2923.5 day cycle. The 8 year short lunisolar cycle was probably known to many ancient cultures. The mathematical proportions of the Octaeteris cycles were noted in Classic Vernal rock art in northeastern Utah
Utah
Utah is a state in the Western United States. It was the 45th state to join the Union, on January 4, 1896. Approximately 80% of Utah's 2,763,885 people live along the Wasatch Front, centering on Salt Lake City. This leaves vast expanses of the state nearly uninhabited, making the population the...
by J. Q. Jacobs in 1990. The Three Kings panel also contains more accurate ratios, ratios related to other planets, and apparent astronomic symbolism.
External links
- http://planetmath.org/encyclopedia/AcanoALunarCalendarMethod.html Acano method for finding 46 lunar eclipses in 270 moons.