orbital element Comparison Table

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orbital element comparison table

Subject has unit is an instance of has symbol has definition has synonym

argument of the perihelion angle unit angle ω Angular distance (measured in the plane of the object's orbit and in the direction of its motion) from the ascending node to the perihelion point. longitude of the perihelion

eccentricity orbital element e The amount by which the elliptical orbit deviates from circularity: e = c/a, where c is the distance from the center to a focus and a is the semimajor axis.

epoch time unit time T A date and time that specifies the reference system to which celestial coordinates are referred. Prior to 1984 coordinates of star catalogs were commonly referred to the mean equator and equinox of the beginning of a Besselian year. Beginning with 1984 the Julian year has been used, as denoted by the prefix J, e.g., J2000.0.

inclination angle unit angle i The angle between two planes or their poles; usually the angle between an orbital plane and a reference plane.

longitude of the ascending node angle unit angle Ω An orbital element representing the point where the body crosses the ecliptic from south to north

period time unit time P An orbital element representing the time required to complete an orbit. This parameter is required when determining the orbit of a binary star system in which the mass is not known.

semimajor axis length unit length a An orbital element representing half the length of the major axis of an ellipse.

Subject	has unit	is an instance of	has symbol	has definition	has synonym
argument of the perihelion	angle unit	angle	ω	Angular distance (measured in the plane of the object's orbit and in the direction of its motion) from the ascending node to the perihelion point.	longitude of the perihelion
eccentricity		orbital element	e	The amount by which the elliptical orbit deviates from circularity: e = c/a, where c is the distance from the center to a focus and a is the semimajor axis.
epoch	time unit	time	T	A date and time that specifies the reference system to which celestial coordinates are referred. Prior to 1984 coordinates of star catalogs were commonly referred to the mean equator and equinox of the beginning of a Besselian year. Beginning with 1984 the Julian year has been used, as denoted by the prefix J, e.g., J2000.0.
inclination	angle unit	angle	i	The angle between two planes or their poles; usually the angle between an orbital plane and a reference plane.
longitude of the ascending node	angle unit	angle	Ω	An orbital element representing the point where the body crosses the ecliptic from south to north
period	time unit	time	P	An orbital element representing the time required to complete an orbit. This parameter is required when determining the orbit of a binary star system in which the mass is not known.
semimajor axis	length unit	length	a	An orbital element representing half the length of the major axis of an ellipse.

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