In a place whose latitude is + 45њ (north), a star was observed with an azimuth of a = 120њ Ost, and an altitude of h = 30њ;

In a place whose latitude is + 45њ (north), a star was observed with an azimuth of a = 120њ Ost, and an altitude of h = 30њ; find its hour angle t and declination d.

Let us set aside the eye on the horizon ISK = a = 120 њOst, draw a vertical circle ZMK through the zenith Z and point K, and put PCM = h = 30њ on it, then this star will be located at point M. Having drawn through M and P the declination circle, the PMR circle, we get the required: hour angle t = ИEWQR, which will be approximately equal to 275њ and declination d = И RM, equal to approximately + 40њ.