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.
When combined with declination, these astronomical coordinates specify the direction of a point on the celestial sphere in the equatorial coordinate system. Right ascension and declination as seen on the inside of the celestial sphere.The primary direction of the system is the vernal equinox, the ascending node of the ecliptic (red) on the celestial equator (blue). Right ascension is measured eastward along the celestial equator from the primary direction.ight ascension is the celestial equivalent of terrestrial longitude. Both right ascension and longitude measure an angle from a primary direction (a zero point) on an equator.