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Perigee

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Perigee
The Moon moves around the Earth in an elliptical orbit (the orbit has been exaggerated in this diagram). The Moon is at perigee when it is is closest to the Earth.


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Definition: perigee: The point in its orbit where an Earth satellite is closest to the Earth. Opposite of apogee.
Space Tragedies9 Planets in Nine DaysAstronomy 101
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Perigee
Science Astronomy
Science Physics
For an object orbiting the Earth (or, since the Interplanetary Age, for any planet), the perigee is the point in each orbit which is closest to the primary. The perigee generally varies a small amount from orbit to orbit.

Perigee and Apogee. These are the minimum and maximum distances from the Earth of a satellite or other body.
Perihelion and Aphelion are the minimum and maximum distances from the Sun of a planet or other body.

Perigee: point in the Moon's orbit when it is nearest to Earth.
Stationary: Object appears motionless in the sky due to the turning point between its direct and retrograde motion.
Find your inner astronomer. Your complete guide to amateur astronomy.

perigee -- the point in the orbit of the Moon that is closest to the Earth.
perihelion -- the point in the orbit of the Earth that is closest to the Sun. Currently the Earth reaches perihelion in early January.
prominence -- a large-scale gaseous formation above the surface of the Sun.

PERIGEE - The point in a satellite’s or the Moon’s orbit when it is closest to Earth. At this point, the object is moving at its maximum speed (Kepler's Second Law). The perigee refers specifically to orbits around the Earth, and is equivalent to the periapsis of a general orbit.

Perigee
The point at which a body in orbit around the Earth most closely approaches the Earth. Perigee is sometimes used with reference to the apparent orbit of the Sun around the Earth.
Perihelion ...

Perigee. The point where (and when) an object's orbit about the earth in which it is closest to the earth; only applicable to objects orbiting the earth (not to objects orbiting the sun --- a common error).

Perigee The position in a geocentric orbit at which the orbiting object is at its least distance from Earth.
Perihelion The position in a heliocentric orbit at which the orbiting object is at its least distance from the Sun.

perigee
The point in its orbit where a satellite or the Moon is nearest the Earth.
perihelion
The point in its orbit where a planet is nearest the Sun.

perigee
The point in the orbit closest to the Earth.
perihelion
The point in its orbit where a planet is closest to the Sun. when referring to objects orbiting the Earth the term perigee is used; the term periapsis is used for orbits around other bodies. (opposite of aphelion) ...

perigee
The point in its orbit where the Moon is at its closest to the Earth. Opposite of apogee.
perihelion
The point in its orbit where a planet is at its closest to the Sun. Opposite of aphelion.

Perigee
the point in the orbit of the Moon or other satellite at which it is closest to the Earth.
Perihelion
the point in the orbit of a planet or other body where it is closest to the Sun.

Perigee. The position of the Moon in its orbit when it is closest to the Earth.
Perihelion. The position of the Earth (or other planet) in its orbit when it is closest to the Sun.
Period. The interval between successive occurrences of a cyclical event.

perigee: The orbital point of closest approach to Earth.
perihelion: The orbital point of closest approach to the sun.
period-luminosity relation: The relation between period of pulsation and intrinsic brightness among Cepheid variable stars.

Perigee -- the point of a satellite's orbit closest to Earth (see perihelion, apogee).
Perihelion -- The point in a planet's orbit when it is closest to the Sun (Helios is Greek for Sun). See aphelion, perigee ...

Perigee:
The point in the orbit of the moon or artificial satellite nearest the earth.
Perihelion:
The point on an orbit nearest the sun.

Perigees and apogees recur on or near the same calendar dates every four years.
A Parting Word ...

Perigee
The point in an objects orbit around the Earth when it is closest to the Earth.
Perihelion ...

At perigee or apogee, there is NO libration of longitude. Maximum librations are seen about one week AFTER perigee and one week AFTER apogee, each time revealing about 8 degrees of longitude on the Moon's far side.

At perigee, the full Moon is about 14% larger in diameter and 30% brighter than a full Moon at apogee, when it's furthest away. Compared to its average distance, it's 7% larger in diameter and 15% brighter. If you're an experienced Moon watcher, you'll see the difference this weekend.

at perigee, marking a so-called 'Supermoon.' See amazing photos of the biggest full moon of 2014 here in this gallery. Shown Here: Astrophotographer Fernando Roquel Torres sent in a photo of the supermoon taken in Caguas, Puerto Rico on Aug. 10, 2014. Less «
2 of 21 ...

Apogee - Perigee Photographic Size Comparison
Aphelion - Perihelion Photographic Size Comparison
Aphelion - Perihelion Dates and Times
v - d - e ...

>"Supermoon" perigee: out of the ordinary, but didn't obtain at time of earthquake-more than a week off still.
>"Supermoon" caused Earthquake? No.
I've yet to see any "argument" here that refutes this really quite simple and I should think not terribly controversial point.

perigee perihelion point in the path of a body orbiting the Sun where it is closest to the Sun. period period table period-luminosity relation perturbation disturbance in the normal movement of an orbiting body arising from an external force, usually gravitational.

Perigee and Apogee
The largest separation between the Earth and Moon on its orbit is called apogee and the smallest separation is called perigee.

2616 light years penumbra the incomplete part of a shadow surrounding the umbra perigee the innermost point of a terrestrial orbit perihelion the innermost point of a solar orbit phase the fracton of the illuminated part of the Moon or other planetary object as seen by the observer ...

when referring to objects orbiting the Earth the term perigee is used; the term periapsis is used for orbits around other bodies. (opposite of aphelion) Perrine, Charles Dillon 1867-1951 Argentine-American astronomer who discovered Himalia and Elara.

peri A prefix meaning near as in perigee. periapsis The orbital point nearest the center of attraction. See orbit. periastron That point of the orbit of one member of a binary star system at which the stars are nearest to each other.

anomalistic month (NASA SP-7, 1965) The average period of revolution of the moon from perigee to perigee, a period of 27 days 13 hours 18 minutes 33.2 seconds. anomalistic period (NASA SP-7, 1965) The interval between two successive perigee passages of a satellite in orbit about a primary.

After launch on an M-V-3 launch vehicle Nozomi was put into an elliptical geocentric parking orbit with a perigee of 340 km and an apogee of 400,000 km. The spacecraft used a lunar swingby on 24 September and another on 18 December, 1998 to increase the apogee of its orbit.

This means there's a fairly large difference between the perigee (when the Moon is at the closest point in its orbit) and apogee (when the Moon is at its farthest). This means that the Earth-Moon distance varies by about 13,000 miles either direction of the average distance.

Cosmos 135 was launched 12 December 1966 into an orbit with 660 km apogee, 250 km perigee, and 49 degree inclination. Cosmos 163 was put into an almost identical orbit on 5 June 1967.
Instrumentation
Identical instruments were carried on both these missions.

This very high tide occurs when the moon is both unusually close to the Earth (at its closest perigee, called the proxigee) and in the New Moon phase (when the Moon is between the Sun and the Earth). The proxigean spring tide occurs at most once every 1.5 years.
Neap Tides ...

Usually a satellite's orbit is an ellipse with a perigee altitude and an apogee altitude.

Another requirement is for the Moon to be near perigee (closest to Earth), when it will make the quickest possible getaway from the Sun's vicinity.

anomalistic month Time taken for the Moon to complete a single orbit around the Earth, measured from perigee to perigee. An anomalistic month is shorter than the more commonly used synodic month, being equivalent to 27.55455 days of mean solar time.

On the third revolution the perigee was raised to 230 km to ensure an orbital lifetime of 15 days. On December 6, 45 hours into the mission, Lovell removed his spacesuit to evaluate the shirtsleeve environment. The first five days were spent conducting experiments and spacecraft tests.

the anomalistic, or time of revolution from perigee to perigee again, in length 27 d. 13 h. 18 m. 37.4 s.; and the tropical, or time of passing from any point of the ecliptic to the same again, equal to 27 d. 7 h. 43 m. 4.7 s.

The closest point a satellite comes to Earth is called its perigee. The farthest point is the apogee. For planets, the point in their orbit closest to the sun is perihelion. The farthest point is called aphelion. Earth reaches its aphelion during summer in the Northern Hemisphere.

Based on the data presented in the Moon's data box, verify the values given for the Moon's perigee (minimum distance from Earth) and apogee (maximum distance from Earth), and estimate the Moon's minimum and maximum angular diameter, as seen from Earth.


PROXIGEE
For an object orbiting the Earth, the proxigee is the closest perigee. The perigee is the point in each elliptical orbit which is closest to the Earth, but the perigee varies a small amount from orbit to orbit.
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June 14 - 11:29 P.M. EDT: The Moon is at perigee, the point in its orbit when it is nearest to Earth.
June 18 - 6 A.M. EDT: The Moon is 5 north of Neptune.
June 19 - 2:39 P.M. EDT: Last Quarter Moon. 7 P.M. EDT: Mercury is in inferior conjunction with the Sun.

This happens when the Moon is near perigee and its angular diameter as seen from Earth is identical to or slightly larger than that of the Sun. A total solar eclipse is the only opportunity to observe the Sun's corona without specialised equipment.

For example, look for perigee and apogee at Earth, perijove and apojove at Jupiter, periselene and apselene or perilune and apolune in lunar orbit, pericrone and apocrone if you're orbiting Saturn, and perihelion and aphelion if you're orbiting the sun, and so on.
Freefall ...

The interval (27.555 days) between two successive perigee passages of the Moon.[H76]
Anomalistic Year
The interval (365.2596 ephemeris days) between two successive perihelion passages of Earth. [H76]
Anomalous Dispersion ...

Aphelion / Perihelion is an object's orbital point (in distance and time) around a star where the object's distance (on its elliptical orbit) from its parent star is farthest / closest. The terms apogee & perigee are used instead when referring to objects orbiting the Earth (e.g. the Moon); ...

Barry Golson, editor. The Playboy Interview Volume II. New York: Wideview/Perigee, 1983. ISBN 0-399-50768-X (hardcover), ISBN 0-399-50769-8 (softcover)
David Sheff, interviewer; G. Barry Golson, editor. The Playboy Interviews with John Lennon ...

Bertotti, Bruno; Ignazio Ciufolini & Peter L. Bender (1987), " New test of general relativity: Measurement of de Sitter geodetic precession rate for lunar perigee", Physical Review Letters 58: 1062-1065, DOI 10.1103/PhysRevLett.58.1062 ...

Annular eclipse for May 2012
The Moon at Perigee and Apogee - Inconstant Moon
Just to be Clear: The Moon Did Not Cause the Earthquake in Japan - Universe Today
Moon Phases 2011 - Universe Today
Moon Phases 2012 - Universe Today ...

On that site grew the city of Canopus (the modern Abu Qir) at the mouth of the Nile. Fittingly, modern space probes now use Canopus as a navigation star. Eratosthenes also knew this star by the name Perigee, in reference to the fact that it remained close to the horizon.

Perigee
Point of closet approach to the earth
Perihelion
Point in earth's orbit around the sun where it is closest to the Sun (winter for us)
Period-Luminosity Diagram
A graph showing the relation-between period of pulsation and intrinsic brightness among Cepheid variable stars.
Photometer ...

See also: See also: Earth, Orbit, Astro, Moon, Sun

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