True longitude

From Wikipedia, the free encyclopedia

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 central object at which the body would be located at a particular time.

[edit] Calculation

The true longitude $l\,$ can be calculated as follows:

$l=\bar{\omega} + v\,$

where:

$\bar{\omega}\,$ is longitude of orbit's periapsis,
$v\,$ is orbit's true anomaly.

v • d • e Orbits

Orbit types by characteristics:	Box orbit \| Circular orbit \| Ecliptic orbit \| Elliptic orbit \| Highly Elliptical Orbit \| Graveyard orbit \| Hyperbolic trajectory \| Inclined orbit \| Osculating orbit \| Parabolic trajectory \| Capture orbit \| Escape orbit \| Semi-synchronous orbit \| Subsynchronous orbit \| Synchronous orbit
Earth-centered orbits:	Geosynchronous orbit \| Geostationary orbit \| Sun-synchronous orbit \| Low Earth orbit \| Medium Earth Orbit \| Molniya orbit \| Near equatorial orbit \| Orbit of the Moon \| Polar orbit \| Polar sun synchronous orbit \| Tundra orbit
Orbits about other bodies:	Areosynchronous orbit \| Areostationary orbit \| Lunar orbit \| Heliocentric orbit \| Heliosynchronous orbit

Orbital elements:	Inclination ( $i\,\!$ ) \| Longitude of the ascending node ( $\Omega\,\!$ ) \| Eccentricity ( $e\,\!$ ) \| Argument of periapsis ( $\omega\,\!$ ) \| Semimajor axis ( $a\,\!$ ) \| Mean anomaly at epoch ( $M_o\,\!$ )
Other orbital parameters:	True anomaly ( $v\,$ ) \| Semi-major axis ( $a\,$ ) \| Semi-minor axis ( $b\,$ ) \| Linear eccentricity ( $\epsilon\,$ ) \| Eccentric anomaly ( $E\,$ ) \| Mean longitude ( $L\,$ ) \| True longitude ( $l\,$ ) \| Orbital period ( $T\,$ )
Orbital maneuvers:	Bi-elliptic transfer \| Geostationary transfer orbit \| Gravitational slingshot \| Hohmann transfer orbit \| Orbital inclination change \| Orbit phasing \| Space rendezvous

Other orbital mechanics topics:	Apsis \| Celestial coordinate system \| Delta-v budget \| Epoch \| Ephemeris \| Equatorial coordinate system \| Ground track \| Interplanetary Transport Network \| Kepler's laws of planetary motion \| Lagrangian point \| List of orbits \| n-body problem \| Orbit equation \| Orbital state vectors \| Retrograde and direct motion \| Specific orbital energy \| Specific relative angular momentum