equatorial Coordinates

They are reported to fixed references on the celestial sphere, therefore they do not vary with the position of the observer and the diurnal motion of s. the c.

They are taken like references:

* the celestial Equator;
* the hour circles;
* the ram point (), point of the celestial Equator in which the Sun is found when spring equinox passes from the celestial hemisphere south to thatnorth ().

The declination () of a star is its angular distance from the celestial Equator (from -90°, to the South Pole, +90° to the North Pole).
The right ascension () of a star is the angular distance between the intersection with the celestial Equator of its hour circle and the point of ram, measured towards east. The right ascension can also be expressed in second hours, minuteren and, placing 1 hour = 15°.

To times, in place of the declination the polar distance is used (p), that it is the angular distance of the star from the celestial North Pole and that varies from 0° to 180°. In any case, p +? = 90°.