Equatorial coordinates কী?

The declination $\delta$ of a star is its angle from the celestial equator, positive to the north, from $-90{}^{\circ}$ to $90{}^{\circ}$. The great circle through the star and the celestial poles is its hour circle. The hour angle $H$ of the star is the angle at the celestial pole between the local meridian and the star’s hour circle, counted westward, in hours of $15{}^{\circ}$. The right ascension $\alpha$ is the angle along the celestial equator from a fixed point of the sky, the vernal equinox point (Definition 1.12), to the star’s hour circle, counted eastward, also in hours.