Right ascension and declination

The celestial coordinate system works as the earth system, but the latitude and longitude are called declination and right ascension.

Right Ascension (AR) is represented by the Greek letter alpha (a) and that is measured from T to m (from the point of the vernal equinox) - Aries point - to the hour circle that passes through the star point m, marked with a thicker line in the figure. Right ascents are measured to the opposite side of the diurnal rotation of the celestial sphere in the limits of 0 to 24 hours in hourly measure.

Declination (D) that is represented by the Greek letter delta (d ) and is the arc that begins at the point located on the star M, up to where it crosses the celestial equator, point m. The declinations are measured from the celestial equator 0º to the celestial Pole 90º point P, being positive all those that go from the celestial equator to the North or Boreal Pole and negative all those that run from the celestial equator to the South or Austral Pole.