Longitude of the periapsis
- Longitude of the periapsis
In astrodynamics, the longitude of the periapsis (symbolized ) of an orbiting body is the longitude (measured from the point of the vernal equinox) at which the periapsis (closest approach to the central body) would occur if the body's inclination were zero. The longitude of periapsis is a compound angle, with part of it being measured in the plane of reference and the rest being measured in the plane of the orbit. Likewise, any angle derived from the longitude of periapsis (e.g. mean longitude and true longitude) will also be compound.
Calculation from state vectors
can be calculated from longitude of ascending node and argument of periapsis :
which are derived from orbital state vectors.
Wikimedia Foundation.
2010.
Look at other dictionaries:
Argument of periapsis — The argument of periapsis (or argument of perifocus) ( ω ) is the orbital element describing the angle of an orbiting body s periapsis (the point of closest approach to the central body), relative to its ascending node (the point where the body… … Wikipedia
Mean longitude — In astrodynamics or celestial dynamics, mean longitude is the longitude at which an orbiting body could be found if its orbit were circular, and free of perturbations, and if its inclination were zero. Both the mean longitude and the true… … Wikipedia
Orbit of the Moon — Not to be confused with Lunar orbit in the sense of a selenocentric orbit, that is, an orbit around the Moon The Moon completes its orbit around the Earth in approximately 27.3 days (a sidereal month). The Earth and Moon orbit about their… … Wikipedia
True longitude — In astrodynamics true longitude is the longitude at which an orbiting body could actually be found if its inclination were zero. Together with the inclination and the ascending node, the true longitude can tell us the precise direction from the… … Wikipedia
Apsis — For the architectural term, see Apse. Aphelion and Perihelion redirect here. For Edenbridge s Album, see Aphelion (album). Apogee and Perigee redirect here. For the literary journal, see Perigee: Publication for the Arts. For other uses, see… … Wikipedia
Semi-major axis — The semi major axis of an ellipse The major axis of an ellipse is its longest diameter, a line that runs through the centre and both foci, its ends being at the widest points of the shape. The semi major axis is one half of the major axis, and… … Wikipedia
Semi-minor axis — The semi minor axis of an ellipse In geometry, the semi minor axis (also semiminor axis) is a line segment associated with most conic sections (that is, with ellipses and hyperbolas). One end of the segment is the center of the conic section, and … Wikipedia
Equation of time — The equation of time is the difference over the course of a year between time as read from a sundial and time as read from a clock, measured in an ideal situation (ie. in a location at the centre of a time zone, and which does not use daylight… … Wikipedia
Orbital elements — are the parameters required to uniquely identify a specific orbit. In celestial mechanics these elements are generally considered in classical two body systems, where a Kepler orbit is used (derived from Newton s laws of motion and Newton s law… … Wikipedia
Orbit — This article is about orbits in celestial mechanics, due to gravity. For other uses, see Orbit (disambiguation). A satellite orbiting the Earth has a tangential velocity and an inward acceleration … Wikipedia
