RA is the abbreviation for right ascension, while DEC stands for the declination. These
coordinates indicate the current position of a star.
The right ascension and declination correspond to the latitude and longitude of the Earth but relate to the sky. The equatorial grid is thus a geocentric coordinate system on the celestial sphere. In this rotating system, the center of the Earth forms the mid-point of the calculations. It is used to indicate the positions of celestial objects. Zero longitude is the moment in which the ecliptic crosses the Earth’s equator and thus reaches the vernal equinox.