longitude of the ascending node Quick reference
A Dictionary of Astronomy (3 ed.)
... of the ascending node ( symbol Ω ) The angle measured along the ecliptic from the vernal equinox eastwards to the ascending node of a planet’s orbit. It defines the point at which an object’s orbit crosses the plane of the Earth’s orbit. See also elements, orbital...
longitude of the ascending node
longitude at the epoch
ascending node
longitude of perihelion
elements, orbital
longitude of perigee
secular perturbation
elements of an orbit
longitude at the epoch Quick reference
A Dictionary of Astronomy (3 ed.)
... at the epoch ( symbol L ) The longitude that a planet has at a particular date and time. It is the angle measured along the ecliptic from the vernal equinox eastwards to the ascending node (i.e. to the longitude of the ascending node), and then eastwards along the orbital plane to the planet’s position at that instant. In the diagram, the longitude at the epoch is the angle γ SN plus the angle NSP. See also elements, orbital . longitude at the epoch: N ascending node P planet S Sun γ vernal equinox Ω longitude of the ascending node ...
longitude of perihelion Quick reference
A Dictionary of Astronomy (3 ed.)
... of perihelion ( symbol ϖ ) The angle measured from the vernal equinox eastwards along the ecliptic to the ascending node of a planet’s orbit, and then continued eastwards along the orbital plane to the perihelion. In other words, it is the longitude of the ascending node added to the argument of perihelion . See also elements, orbital...
ascending node Quick reference
A Dictionary of Astronomy (3 ed.)
... node ( symbol ☊ ) The point in an orbit at which a body moves from south to north across a reference plane, such as the plane of the ecliptic or of the celestial equator. The longitude of the ascending node is one of the elements of an object’s orbit. See Elements, Orbital ; Node...
secular perturbation Quick reference
A Dictionary of Astronomy (3 ed.)
...perturbation A perturbation in a body’s orbit that is cumulative, causing an orbital element to grow or decrease. The gravitational attractions of the planets upon each other cause secular changes in the longitude of the ascending node, longitude of perihelion, and times of perihelion passage, as well as causing periodic...
longitude of perigee Quick reference
A Dictionary of Astronomy (3 ed.)
... of perigee For the Moon or an artificial Earth satellite, the angle measured from the direction of the vernal equinox eastwards along the celestial equator to the ascending node of the satellite’s orbit, and then continued eastwards along the orbital plane to the satellite’s...
elements of an orbit Quick reference
A Dictionary of Physics (8 ed.)
...of an orbit Six parameters that can be used to define the path of a celestial body. The shape of the orbit is defined by its eccentricity ( see conic ) and semimajor axis. The orientation of the orbit is specified by the inclination of the orbital plane to the reference plane (usually the ecliptic ) and by the longitude of the ascending node (the angular distance from the vernal equinox to the ascending node). The position of the body in its orbit is defined by its eccentric anomaly and the position as a function of time is calculated from the...
elements, orbital Quick reference
A Dictionary of Astronomy (3 ed.)
...the size, shape, and orientation of an orbit. They can be used to calculate the position of a body in its orbit at any given time. For planets orbiting the Sun, the ecliptic and the vernal equinox (the first point of Aries) are used as a reference plane and reference direction respectively ( see the diagram ). The orbital elements are then: the longitude of the ascending node , Ω ; the inclination , i ; the argument of perihelion , ω ; the semimajor axis , a ; the eccentricity , e ; and a final number that gives the position of the planet in the...
Orbital Parameters and Equations Reference library
Encyclopedia of Climate and Weather (2 ed.)
...in the plane of reference and 90° from x , while the z -axis is taken to be perpendicular to this reference plane, so that the three axes form a right-handed coordinate system. The reference point from which the angles are measured is γ 0 . As the reference plane is usually chosen to be the ecliptic at a particular fixed date of reference (called the epoch of reference in celestial mechanics; Woolard and Clemence, 1966 ), γ 0 is, in such a case, the vernal point at that fixed date. P is the perihelion; Ω is the longitude of the ascending node; ω is the...
geodesy and geodetic measurements Reference library
The Oxford Companion to the Earth
...to the centre of mass of the Solar System) reference frame. In either case, the system is defined with respect to the ecliptic, the plane of the Earth's orbit around the Sun, and the Earth's Equator. The line of intersection of these two planes marks the equinoxes, the points at which the Sun apparently crosses the Equator as it passes from one hemisphere to the other. The vernal equinox (also known as the ascending node), where the Sun passes from the southern to the northern hemisphere, is chosen as the fundamental axis of the reference frame. Like the...
Guō Shǒujìng (1231–1316) Reference library
George LANE
The Berkshire Dictionary of Chinese Biography
...the House of Tolui as Möngke Khan (r. 1251–1259 ) ascended the throne, heralding great change throughout much of the empire. Möngke Khan quickly dispatched his two brothers to the east and to the west to consolidate his hold on power and to establish his vision of a global, multicultural empire based on trade and the accumulation of wealth. In the west, Hulegu Khan ( d. 1265 ) founded the Ilkhanate ( 1258–1335 ): a culturally rich Turko-Persian trading nation, which was a forerunner to the re-birth of Iran as a political and mercantile world player. In the...
