What's the meaning of the star coordinates?
Naming a Star you have made an important person in your life very happy. Or have you been surprised yourself with this unique gift? Then you are certainly looking for your Star in the Nightsky. The Star Certificate is an aid to find it, because it contains your registration number as well as the coordinates of your named star. In this article we would like to explain to you the meaning of those coordinates.
RA and DEC coordinates
On your individual star certificate, you will find the coordinates of your named star, which are marked with RA and DEC. RA is the abbreviation for right ascension, while DEC stands for declination. The right ascension and declination correspond to the longitude and latitude of the Earth but refer to the sky. The equatorial grid is thus a geocentric coordinate system on the celestial sphere. With this rotating system, the center of the earth forms the center of the calculations. It is used to indicate the positions of celestial objects. The zero longitude corresponds to the moment when the earth equator intersects the ecliptic and thus reaches the vernal equinox.
Units of the Star Coordinates
Normally, angles are given in degrees. However, the Earth always needs 24 hours to rotate around its own axis. Per hour 15° of the longitudes (RA) move over a fixed point on earth (360°/24h = 15°/h). Due to this regularity, a division into hours can be used instead of the degrees. Therefore, the coordinates on your star certificate are partly provided with time data. This procedure has the advantage that observers can determine the time of the appearance of a following celestial body at the same point. The declination corresponds to the celestial latitude and is given a degree like on Earth. The celestial north pole is at +90°, while the celestial south pole is at -90°.