Eclipse Obscuring of one celestial body by another, either by direct superposition or by the casting of a shadow.
Lunar eclipses are of two types, total and partial.
Ellipse Oval path of a planet around the sub, with the sun at one of the two foci. When, as viewed from the earth, an inferior planet attains its greatest angular distance from the sun, it is said to be at either western or eastern elongation. Equator, celestial A great circle on the celestial sphere midway between the two apparent poles of rotation. It corresponds to the plane of the earth's equator extended until it cuts the sphere. Equator, galactic A great circle drawn along the Milky Way.