9 articles for "Ecliptic"Ecliptic [Astro*Index]
The great circle formed by the intersection of the plane of the Ecliptic with the Celestial Sphere.Ecliptic [Prima]
The apparent path of the Sun's yearly motion through the zodiac as projected against the celestial sphere in Earth-centered astronomy (and geocentric astrology).
The plane of the ecliptic is actually the plane of the barycenter of the Earth-Moon system; it is sometimes loosely defined as the mean plane of the Earth's orbit.
The ecliptic is inclined at 23°5" to the celestial equator.Ecliptic [Munkasey M.]
That great circle of the Celestial Sphere which the Suntraces in its apparent yearly motion through the heavens. The Ecliptic, for astrological purposes, is divided into twelve equal divisions of thirty degrees each. These measurements, called "signs", start at the Aries point. Each division of the Ecliptic is a sign of the zodiac. Measurements along the Ecliptic are in degrees of zodiacal longitude and give the angular distance between bodies which are referred to as "aspects".Ecliptic Coordinates [Astro*Index]
Celestial Longitude and Latitude. Celestial Longitude is measured along the Ecliptic from a specified fiducial point to the foot of a great circle which passes through the body and is perpendicular to the Ecliptic. If the Vernal Point is used as the fiducial, the coordinates are said to be measured in the Tropical zodiac; if the fiducial of the Sidereal Zodiac is used, the coordinates are said to be Sidereal. Celestial Latitude is measured along the perpendicular great circle from the Ecliptic to the body; + if north, - if south.Ecliptic Intersect [Astro*Index]
The point on the Celestial Sphere where an Hour Circle intersects the Ecliptic.
See also:Ecliptic Intersect [Munkasey M.]
♦ Celestial Sphere ♦ Hour Circle
The name for that point in space where an HourCircle intersects the Ecliptic.
See also:Ecliptic; Via Solis, the Sun's path [DeVore]
♦ Celestial Sphere ♦ Hour Circle
The Sun's apparent orbit or path around the Earth; or the orbit of the Earth as viewed from the Sun. So named because it is along this path, at the points where it intersects the Equator, that Eclipses occur. Its inclination (23°27') to the plane of the Equator is now decreasing at the rate of 50" per century. A comparison of the calculations of this obliquity by Hipparchus, Ptolemy and Placidus, with those of modern astronomers, shows that the decrease has been continuous for over two thousand years. Discoveries of explorers in the Arctic and Antarctic regions indicate the one-time presence of tropical flora and fauna, suggesting that the poles of the earth were once in the plane of its orbit, and the present equatorial region was a great ice-belt. However, some astronomers figure that the inclination will decrease to a minimum of 22°30' in about the year 11,500. A similar condition is observed in Mars and Uranus. Sometimes termed the Celestial Ecliptic to distinguish it from the path of the Moon's orbit around the Earth-termed the Terrestrial Ecliptic.Ecliptic Plane [Astro*Index]
The plane of the Barycenter (of the Earth-Moon System). Sometimes loosely defined as the mean plane of the Earth's orbit. Frequently incorrectly defined as the plane of the Earth's orbit about the Sun. (Note that the Geocentric Longitude of the Sun is not identically zero, as it would be if the Ecliptic Plane were the same as the Instantaneous Orbital Plane of the Earth.)
See also: ♦ BarycenterEcliptic Pole [Astro*Index]
Each of the points which lie 90° from the Ecliptic circle.
Astro*Index Copyright © 1997 Michael Erlewine
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