synodic period


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Related to synodic period: Sidereal period, synodic month

synodic period

(sĭnŏd`ĭk), in astronomy, length of time during which a body in the solar system makes one orbitorbit,
in astronomy, path in space described by a body revolving about a second body where the motion of the orbiting bodies is dominated by their mutual gravitational attraction.
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 of the sun relative to the earth, i.e., returns to the same elongationelongation,
in astronomy, the angular distance between two points in the sky as measured from a third point. The elongation of a planet is usually measured as the angular distance from the sun to the planet as measured from the earth.
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. Because the earth moves in its own orbit, the synodic period differs from the sidereal period, which is measured relative to the stars. The synodic period of the moon, which is called the lunar month, or lunation, is 29 1-2 days long; it is longer than the sidereal month. The moon is full when it is at oppositionopposition,
in astronomy, alignment of two celestial bodies on opposite sides of the sky as viewed from earth. Opposition of the moon or planets is often determined in reference to the sun.
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. One sidereal month later it will not yet be full, since it must travel further in its orbit around the earth to reach the point of opposition, which has moved relative to the stars because of the earth's motion. Since the calendar month is not equal to the lunar month, the full moon does not occur on the same day every month. The length of time between recurrences of the full moon on the same date is 235 lunar months, or 19 years. This period, called the Metonic cycle, was discovered by the Greek astronomer Meton in 433 B.C. It is used in determining the date of Easter in the Gregorian calendarcalendar
[Lat., from Kalends], system of reckoning time for the practical purpose of recording past events and calculating dates for future plans. The calendar is based on noting ordinary and easily observable natural events, the cycle of the sun through the seasons with equinox
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 and was used in placing the intercalary month in the ancient Greek calendar. For the inferior planetsinferior planet,
planet whose orbit lies inside that of the earth. There are two inferior planets, Mercury and Venus. They always seem to be close to the sun in the sky; the greatest elongation of Mercury is 28°, and that of Venus, 47°.
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 the synodic period is longer than the sidereal period, but for the superior planetssuperior planet,
planet whose orbit lies outside that of the earth. The superior planets are Mars, Jupiter, Saturn, Uranus, and Neptune.
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 it is shorter.
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synodic period

The average time between successive conjunctions of two planets as seen from the Earth, or between successive conjunctions of a satellite with the Sun as seen from the satellite's primary. Synodic period, P s, and sidereal period, P 1, of an inferior or superior planet are related, respectively, by the equations
1/P s = 1/P 1 – 1/P 2
1/P s = 1/P 2 – 1/P 1

P 2 is the sidereal period of the Earth, i.e. 365.256 days or 1 year. For a satellite the first equation applies, P 2 being the sidereal period of the primary.

Collins Dictionary of Astronomy © Market House Books Ltd, 2006

Synodic Period

(religion, spiritualism, and occult)

A synodic period (from the Greek, meaning “to meet or travel together”) is the period a heavenly body takes to move from one conjunction with the Sun to the next. A synodic month, for example, is the period of time between successive new moons (which is 29 days 12 hours 44 minutes). Because Earth is always moving forward in its orbit, the time it takes the Moon to complete a synodic month differs from the time it takes the Moon to return to its original position relative to the backdrop of the comparatively stationary stars. Synodic cycle refers to the time between the conjunctions of two planets (not to the time between the conjunctions of a planet and the Sun).

The Astrology Book, Second Edition © 2003 Visible Ink Press®. All rights reserved.
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Synodic Period

 

the time interval during which a planet, moving in orbit around the sun, returns to its former position relative to the sun as seen from the earth. For example, the synodic period of Venus is the time between successive identical phases. The synodic period represents the time necessary for the repetition of a planet’s configuration.

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.

synodic period

[sə′näd·ik ′pir·ē·əd]
(astronomy)
The time period between two successive astronomical conjunctions of the same celestial objects.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.

synodic period

synodic periodclick for a larger image
The time interval between the identical position of a celestial body in the solar system measured with respect to the sun.
An Illustrated Dictionary of Aviation Copyright © 2005 by The McGraw-Hill Companies, Inc. All rights reserved
References in periodicals archive ?
Recognizing that this number was almost identical to the synodic period of Venus (583.92 days, the time it takes for Venus to return to the same position as seen from Earth), Forstermann determined that the red numbers--236, 90, 250, and 8--marked four significant points in the planet's cycle: its morning heliacal rising; its disappearance at superior conjunction; its first evening rise; and its disappearance at inferior conjunction.
Sharp (2010) suggests another value--171.44a, which is the synodic period of Uranus and Neptune.
So the planet's synodic period, the interval between two inferior conjunctions, is 1.6 years.
Nevertheless, Meeus is careful to explain terms as they are first introduced, such as the synodic period of the Moon (time between successive new Moons), anomalistic month (time between successive perigees), and draconian month (time between passages through a node).
The average interval ("synodic period") between heliocentric conjunctions of Mercury and Jupiter is 89.8 days.
It is well known that oppositions of Mars recur on average every 780 days, or 2.135 years, the planet's synodic period.
One of their calendars, the Tzolkin, makes use of a 260-day interval (almost exactly one-third of Mars's synodic period).
To find the synodic period of each group, he drew a circle to represent the Sun.
Though already by the end of 1883 Schiaparelli had followed Mercury through seven synodic periods and amassed an archive of 150 drawings, his health broke down--probably in part from overwork.