The ecliptic coordinate system is a celestial coordinate system that uses the ecliptic for its fundamental plane. The ecliptic is the path that the sun appears to follow across the sky over the course of a year. It is also the projection of the Earth's orbital plane onto the celestial sphere. The latitudinal angle is called the ecliptic latitude, and the longitudinal angle is called the ecliptic longitude. Like right ascension in the equatorial coordinate system, the zeropoint of the ecliptic longitude is the vernal equinox. In astronomy, a celestial coordinate system is a coordinate system for mapping positions in the sky. ... The plane of the Ecliptic is well seen in this picture from the 1994 lunar prospecting Clementine spacecraft. ... The fundamental plane in a spherical coordinate system is a plane which divides the sphere into two hemispheres. ... The Sun is the star at the centre of our Solar system. ... The word projection can mean more than one thing. ... The orbital plane is an astronomical concept. ... In astronomy and navigation, the celestial sphere is an imaginary rotating sphere of gigantic radius, concentric with the Earth. ... Latitude, denoted by the Greek letter φ, gives the location of a place on Earth north or south of the Equator. ... Ecliptic latitude is one of the co-ordinates which can be used to define the location of an astronomical object on the celestial sphere in ecliptic coordinates. ... Map of Earth showing curved lines of longitude Longitude, sometimes denoted λ, describes the location of a place on Earth east or west of a north-south line called the Prime Meridian. ... Ecliptic longitude is one of the co-ordinates which can be used to define the location of an astronomical object on the celestial sphere in ecliptic coordinates. ... Right ascension (RA; symbol α: Greek letter alpha) is the astronomical term for one of the two coordinates of a point on the celestial sphere when using the equatorial coordinate system. ... The equatorial coordinate system is probably the most widely used celestial coordinate system, whose equatorial coordinates are: declination () right ascension () or hour angle () It is the most closely related to the geographic coordinate system, because they use the same fundamental plane, and the same poles. ... Illumination of Earth by Sun on the day of equinox In astronomy, the vernal equinox (spring equinox, March equinox, or northward equinox) is the moment when the sun appears to cross the celestial equator, heading northward. ...

Such a coordinate system can be useful for charting solar system objects. Each of the planets (except Pluto) orbits the sun in roughly the same plane, so they always appear to be somewhere near the ecliptic (i.e., they always have small ecliptic latitudes). Atmospheric characteristics Atmospheric pressure 0. ... In physics, an orbit is the path that an object makes, around another object, whilst under the influence of a source of centripetal force, such as gravity. ...

This article originates from Jason Harris' Astroinfo which comes along with KStars, a Desktop Planetarium for Linux/KDE. See http://edu.kde.org/kstars/index.phtml Screenshot of KStars showing the night sky from Hanover. ... Tux, a cartoon penguin frequently featured sitting, is the official Linux mascot. ... KDE (Kool Desktop Environment) is a free desktop environment and development platform built with Trolltechs Qt toolkit. ...