Post-concussion syndrome. Post-concussion syndrome, also known as postconcussive syndrome or PCS, is a set of symptoms that may continue for weeks, months, or a year or more after a concussion â a mild form of traumatic brain injury (TBI).
The Equatorial (Celestial) Coordinate System. Equatorial coordinates, also called simply celestial coordinates, are the standard coordinate system for the sky. It is meant for the fixed sphere of the stars within which the Earth and Sun move.
1. celestial equator-the great circle on the celestial sphere midway between the celestial poles. equinoctial, equinoctial circle, equinoctial line. great circle-a circular line on the surface of a sphere formed by intersecting it with a plane passing through the center.. celestial equator-the great circle on the celestial sphere midway between the celestial poles. equinoctial, equinoctial circle, equinoctial line. great circle-a circular line on the surface of a sphere formed by intersecting it with a plane passing through the center.