In a place whose latitude is φ = + 45 ° (N), a star was observed with an azimuth at A = 120 ° and an altitude h = 30 °

In a place whose latitude is φ = + 45 ° (N), a star was observed with an azimuth at A = 120 ° and an altitude h = 30 °; find its hour angle a and declension b

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