# Glossary

Anomaly, True - The true angle, in the plane of an ellipse, between periapsis and the position on the ellipse at a particular time

Anomaly, Mean - The angle between periapse and a particular point on an ellipse assuming uniform angular velocity

Apsides, Line of - The line along an ellipse's semi-major axis between the periaps and apoaps

Apoaps - The furthest distance in an ellipse from the sun

Aries, First Point in - The star in the constellation Aries that defines the x axis

Axis, Major - The longer(or major) axis

Axis, Minor - The shorter(or minor) axis

Axis, Semi-Major - Half of the Major Axis, on the average distance between the periaps and apoaps

Axis, Semi-Minor - Half of the Minor Axis

Circle - A special case of an ellipse whose periaps equals the apoaps, or more simply, where each point is equidistant from it's center

Eccentricity - A constant defining the shape of the conic orbit. Circle(e=0), Ellipse(0<1), Parabola(e=1), or Hyperbola(e>1)

Ecliptic - The Solar System's plane of reference. It is defined to be in the same plane as the Earth's orbit

Ellipse - A conic section cut

Focus, Prime - One of the foci found in an orbital ellipse. This is where the central body is located

Focus, Vacant - One of the foci found in an orbital ellipse

Gravitational Constant, G - Newton's derived constant of gravitation: 6.62759E-20km^3/kg-s^2

Hyperbola - The conic created by the planar intersection of two opposite facing cones

Inclination - The angle between the reference plane(or ecliptic) and an intersecting orbit

Node, Ascending - The rising edge through the Line of Nodes

Node, Descending - The falling edge through the Line of Nodes

Node, Line of - The line of intersection between two planes

Parabola - The conic created by a planar intersection of a cone parallel to its sides

Periaps - The closest distance in an ellipse from the sun

Periaps, Argument of - The angle, in the plane of the satellite's orbit, between the ascending node and the periapsis point, measured in the direction of the satellite's motion

Rising Node, Longitude of - The angle, in the plane of reference, from the First Point in Aries to the Ascending Node on the line of intersection between two orbits (the Line of Nodes).

Semi-Labus Rectum - The line perpindicular to the semi-major axis that intersects the prime focus.