anomalistic months

A Saros cycle is a period of 6585 + 1/3 days (approximately 18 years 10 days and 8 hours) which can be used to predict eclipses of the Sun and the Moon. Every saros the Sun, the Earth and the Moon return to approximately the same places and therefore almost identical solar and lunar eclipses repeat one saros apart. For example, there was a total eclipse of the Sun on 11 August 1999 centred over Europe and there will be a similar eclipse of the Sun on 21 August 2017. Due to the one third of a day fraction, the Earth will be one third of a turn (120 degrees) through its daily rotation so the eclipse will ...

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• Saros cycle - Reference

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Hipparchus astronomer - Motion of the Moon. Hipparchus also studied the motion of the Moon and confirmed the accurate values for some periods of its motion that Chaldean astronomers had obtained before him. The traditional value (from Babylonian System B) for the mean synodic month is 29 days;31,50,8,20 (sexagesimal) = 29.5305941... d. Expressed as 29 days + 12 hours + 793/1080 hours this value has been used later in the Hebrew calendar (possibly from Babylonian sources). The Chaldeans also kn ...

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Hipparchus astronomer, Hipparchus astronomer - Life and work, Hipparchus astronomer - Babylonian sources, Hipparchus astronomer - Geometry and trigonometry, Hipparchus astronomer - Lunar and solar theory, Hipparchus astronomer - Motion of the Moon, Hipparchus astronomer - Orbit of the Moon, Hipparchus astronomer - Apparent motion of the Sun, Hipparchus astronomer - Orbit of the Sun, Hipparchus astronomer - Calendar, Hipparchus astronomer - Distance parallax size of the Moon and Sun, Hipparchus astronomer - Eclipses, Hipparchus astronomer - Astronomical instruments and astrometry, Hipparchus astronomer - Geography, Hipparchus astronomer - Star catalogue, Hipparchus astronomer - Celestial bodies, Hipparchus astronomer - Celestial coordinate systems, Hipparchus astronomer - Brightness of stars, Hipparchus astronomer - Precession of the equinoxes 146 BC-130 BC, Hipparchus astronomer - Hipparchus and astrology, Hipparchus astronomer - Named after Hipparchus, Hipparchus astronomer - Literature

Read more here: » Hipparchus astronomer: Encyclopedia II - Hipparchus astronomer - Lunar and solar theory

The variation in apparent size of the Moon is because the orbit of the Moon is distinctly elliptic, and as a consequence at one time it is nearer to the Earth (perigee) than half an orbit later (apogee). The orbital period of the Moon from perigee to apogee and back to perigee is called the anomalistic month. The appearance, or phase, of the Moon is due to its motion with respect to the Sun. It varies in a period of time called a lunation, also called synodic month. The age is the num ...

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Full moon cycle, Full moon cycle - Explanation, Full moon cycle - Fumocy and the year, Full moon cycle - Matching synodic and anomalistic months, Full moon cycle - Use of fumocy in predicting new and full moons, Full moon cycle - periodic corrections, Full moon cycle - Mean syzygy, Full moon cycle - fumocy correction, Full moon cycle - epochs and constants, Full moon cycle - solar correction, Full moon cycle - statistics

Read more here: » Full moon cycle: Encyclopedia II - Full moon cycle - Explanation

Hipparchus is credited with the invention or improvement of several astronomical instruments, which were used for a long time for naked-eye observations. According to Synesius of Ptolemais (4th century) he made the first astrolabion: this may have been an armillary sphere (which Ptolemy however says he constructed, in Almagest V.1); or the predecessor of the planar instrument called astrolabe (also mentioned by Theon of Alexandria). With an astrolabe Hipparchus was the first to be able to measure the geographical latitude and t ...

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Hipparchus astronomer, Hipparchus astronomer - Life and work, Hipparchus astronomer - Babylonian sources, Hipparchus astronomer - Geometry and trigonometry, Hipparchus astronomer - Lunar and solar theory, Hipparchus astronomer - Motion of the Moon, Hipparchus astronomer - Orbit of the Moon, Hipparchus astronomer - Apparent motion of the Sun, Hipparchus astronomer - Orbit of the Sun, Hipparchus astronomer - Calendar, Hipparchus astronomer - Distance parallax size of the Moon and Sun, Hipparchus astronomer - Eclipses, Hipparchus astronomer - Astronomical instruments and astrometry, Hipparchus astronomer - Geography, Hipparchus astronomer - Star catalogue, Hipparchus astronomer - Celestial bodies, Hipparchus astronomer - Celestial coordinate systems, Hipparchus astronomer - Brightness of stars, Hipparchus astronomer - Precession of the equinoxes 146 BC-130 BC, Hipparchus astronomer - Hipparchus and astrology, Hipparchus astronomer - Named after Hipparchus, Hipparchus astronomer - Literature

Read more here: » Hipparchus astronomer: Encyclopedia II - Hipparchus astronomer - Astronomical instruments and astrometry

Hipparchus is perhaps most famous for having been the first to measure the precession of the equinoxes. There is some suggestion that the Babylonians may have known about precession, but it appears that Hipparchus was the first to really understand it and measure it. According to al-Battani, Chaldean astronomers had distinguished the tropical and sidereal year. He stated that they had, around 330 BC, an estimation for the length of the sidereal year to be SK = 365 days 6 hours 11 min (= 365.258 days) with an er ...

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Hipparchus astronomer, Hipparchus astronomer - Life and work, Hipparchus astronomer - Babylonian sources, Hipparchus astronomer - Geometry and trigonometry, Hipparchus astronomer - Lunar and solar theory, Hipparchus astronomer - Motion of the Moon, Hipparchus astronomer - Orbit of the Moon, Hipparchus astronomer - Apparent motion of the Sun, Hipparchus astronomer - Orbit of the Sun, Hipparchus astronomer - Calendar, Hipparchus astronomer - Distance parallax size of the Moon and Sun, Hipparchus astronomer - Eclipses, Hipparchus astronomer - Astronomical instruments and astrometry, Hipparchus astronomer - Geography, Hipparchus astronomer - Star catalogue, Hipparchus astronomer - Celestial bodies, Hipparchus astronomer - Celestial coordinate systems, Hipparchus astronomer - Brightness of stars, Hipparchus astronomer - Precession of the equinoxes 146 BC-130 BC, Hipparchus astronomer - Hipparchus and astrology, Hipparchus astronomer - Named after Hipparchus, Hipparchus astronomer - Literature

Read more here: » Hipparchus astronomer: Encyclopedia II - Hipparchus astronomer - Precession of the equinoxes 146 BC-130 BC

After that, in 135 BC, enthusiastic about a nova in the constellation of Scorpius, he measured with an equatorial armillary sphere ecliptical coordinates of about 1,000 stars (the exact number is not known) for his star catalogue. He also knew the work Phainomena (Phenomena). That poem, known as Phaenomena or Arateia, describes the constellations and the stars that form them. Hipparchus' commentary contains many measurements of stellar position and times for rising, culmination, and setting of the constella ...

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Hipparchus astronomer, Hipparchus astronomer - Life and work, Hipparchus astronomer - Babylonian sources, Hipparchus astronomer - Geometry and trigonometry, Hipparchus astronomer - Lunar and solar theory, Hipparchus astronomer - Motion of the Moon, Hipparchus astronomer - Orbit of the Moon, Hipparchus astronomer - Apparent motion of the Sun, Hipparchus astronomer - Orbit of the Sun, Hipparchus astronomer - Calendar, Hipparchus astronomer - Distance parallax size of the Moon and Sun, Hipparchus astronomer - Eclipses, Hipparchus astronomer - Astronomical instruments and astrometry, Hipparchus astronomer - Geography, Hipparchus astronomer - Star catalogue, Hipparchus astronomer - Celestial bodies, Hipparchus astronomer - Celestial coordinate systems, Hipparchus astronomer - Brightness of stars, Hipparchus astronomer - Precession of the equinoxes 146 BC-130 BC, Hipparchus astronomer - Hipparchus and astrology, Hipparchus astronomer - Named after Hipparchus, Hipparchus astronomer - Literature

Read more here: » Hipparchus astronomer: Encyclopedia II - Hipparchus astronomer - Star catalogue

Many of the works of Greek scientists - mathematicians, astronomers, geographers - have been preserved up to the present time, or some aspects of their work and thought are still known through later references. However, achievements in these fields by Middle Eastern civilizations, notably those in Babylonia, had been forgotten. After the discovery of the archaeological sites in the 19th century, many writings on clay tablets have been found, some of them related to astronomy. Most known astronomical tablets have been described by A. Sachs, and later published by Otto Neugebauer in "Astrono ...

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Hipparchus astronomer, Hipparchus astronomer - Life and work, Hipparchus astronomer - Babylonian sources, Hipparchus astronomer - Geometry and trigonometry, Hipparchus astronomer - Lunar and solar theory, Hipparchus astronomer - Motion of the Moon, Hipparchus astronomer - Orbit of the Moon, Hipparchus astronomer - Apparent motion of the Sun, Hipparchus astronomer - Orbit of the Sun, Hipparchus astronomer - Calendar, Hipparchus astronomer - Distance parallax size of the Moon and Sun, Hipparchus astronomer - Eclipses, Hipparchus astronomer - Astronomical instruments and astrometry, Hipparchus astronomer - Geography, Hipparchus astronomer - Star catalogue, Hipparchus astronomer - Celestial bodies, Hipparchus astronomer - Celestial coordinate systems, Hipparchus astronomer - Brightness of stars, Hipparchus astronomer - Precession of the equinoxes 146 BC-130 BC, Hipparchus astronomer - Hipparchus and astrology, Hipparchus astronomer - Named after Hipparchus, Hipparchus astronomer - Literature

Read more here: » Hipparchus astronomer: Encyclopedia II - Hipparchus astronomer - Babylonian sources

Formulated in another way: the fumocy is the period that it takes the Sun to return to the perigee of the Moon's orbit. So it is a kind of "perigee year", similar to the eclipse year which is the time for the Sun to return to the ascending node of the Moon's orbit on the ecliptic. Why does a fumocy last almost 14 lunations rather than just the 12.37 lunations of a year? This would be the case, if moon's orbit kept a constant orientation with respect to the stars, but the tidal effect of the sun causes the orbit to precess over a cycle just under 9 years. In that time, the number of fumocies passed bec ...

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Full moon cycle, Full moon cycle - Explanation, Full moon cycle - Fumocy and the year, Full moon cycle - Matching synodic and anomalistic months, Full moon cycle - Use of fumocy in predicting new and full moons, Full moon cycle - periodic corrections, Full moon cycle - Mean syzygy, Full moon cycle - fumocy correction, Full moon cycle - epochs and constants, Full moon cycle - solar correction, Full moon cycle - statistics

Read more here: » Full moon cycle: Encyclopedia II - Full moon cycle - Fumocy and the year

When tracking fumocies by counting cycles of 14 synodic months, a correction of 1 synodic month should take place after 18 fumocies: 18×FC = 251×SM = 269×AM, not: 18×14 = 252×SM The equality of 269 anomalistic months to 251 synodic months was already known to Chaldean astronomers (see Kidinnu). A good longer period spans 55 fumocies or rather 767 synodic months, which is not only very close to an integer number of synodic and anomalistic months, but also when reckoned in synodic months is close ...

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Full moon cycle, Full moon cycle - Explanation, Full moon cycle - Fumocy and the year, Full moon cycle - Matching synodic and anomalistic months, Full moon cycle - Use of fumocy in predicting new and full moons, Full moon cycle - periodic corrections, Full moon cycle - Mean syzygy, Full moon cycle - fumocy correction, Full moon cycle - epochs and constants, Full moon cycle - solar correction, Full moon cycle - statistics

Read more here: » Full moon cycle: Encyclopedia II - Full moon cycle - Matching synodic and anomalistic months

Most of what is known about Hipparchus comes from Ptolemy's (2nd century) Almagest ("the great treatise"; ed. [Toomer 1981]), with additional references to him by Pappus of Alexandria and Theon of Alexandria (4th century) in their commentaries on the Almagest; from Strabo's Geographia ("Geography"), and from Pliny the Elder's Naturalis historia ("Natural history") (1st century). There is a strong tradition that Hipparchus was born in Nicaea (Greek Νικαία), in the ancient district of Bithynia (modern- ...

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Hipparchus astronomer, Hipparchus astronomer - Life and work, Hipparchus astronomer - Babylonian sources, Hipparchus astronomer - Geometry and trigonometry, Hipparchus astronomer - Lunar and solar theory, Hipparchus astronomer - Motion of the Moon, Hipparchus astronomer - Orbit of the Moon, Hipparchus astronomer - Apparent motion of the Sun, Hipparchus astronomer - Orbit of the Sun, Hipparchus astronomer - Calendar, Hipparchus astronomer - Distance parallax size of the Moon and Sun, Hipparchus astronomer - Eclipses, Hipparchus astronomer - Astronomical instruments and astrometry, Hipparchus astronomer - Geography, Hipparchus astronomer - Star catalogue, Hipparchus astronomer - Celestial bodies, Hipparchus astronomer - Celestial coordinate systems, Hipparchus astronomer - Brightness of stars, Hipparchus astronomer - Precession of the equinoxes 146 BC-130 BC, Hipparchus astronomer - Hipparchus and astrology, Hipparchus astronomer - Named after Hipparchus, Hipparchus astronomer - Literature

Read more here: » Hipparchus astronomer: Encyclopedia II - Hipparchus astronomer - Life and work

Hipparchus is recognised as the first mathematician who compiled a trigonometry table, which he needed when computing the eccentricity of the orbits of the Moon and Sun. He tabulated values for the chord function, which gives the length of the chord for each angle. He did this for a circle with a circumference of 21,600 and a radius of (rounded) 3438 units: this has a unit length of 1 arc minute along its perimeter. He tabulated the chords for angles with increments of 7.5°. In modern terms, the chord of an angle equals twice the sine of half of the angle, ...

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Hipparchus astronomer, Hipparchus astronomer - Life and work, Hipparchus astronomer - Babylonian sources, Hipparchus astronomer - Geometry and trigonometry, Hipparchus astronomer - Lunar and solar theory, Hipparchus astronomer - Motion of the Moon, Hipparchus astronomer - Orbit of the Moon, Hipparchus astronomer - Apparent motion of the Sun, Hipparchus astronomer - Orbit of the Sun, Hipparchus astronomer - Calendar, Hipparchus astronomer - Distance parallax size of the Moon and Sun, Hipparchus astronomer - Eclipses, Hipparchus astronomer - Astronomical instruments and astrometry, Hipparchus astronomer - Geography, Hipparchus astronomer - Star catalogue, Hipparchus astronomer - Celestial bodies, Hipparchus astronomer - Celestial coordinate systems, Hipparchus astronomer - Brightness of stars, Hipparchus astronomer - Precession of the equinoxes 146 BC-130 BC, Hipparchus astronomer - Hipparchus and astrology, Hipparchus astronomer - Named after Hipparchus, Hipparchus astronomer - Literature

Read more here: » Hipparchus astronomer: Encyclopedia II - Hipparchus astronomer - Geometry and trigonometry