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.
Celestial Longitude: Right Ascension. â¢ The celestial equivalent to longitude is called right ascension. Itâs measured not in degrees but in âhoursâ, from 0h to 24h. Astronomers cooked up this arrangement long ago because the celestial sphere appears to turn once every 24 hours.