...horizon is the meridian; second, the vertical circle at right angles to the plane of the meridian, and passing through the east and west points of the horizon, is called the prime vertical. Any small circle of the celestial sphere cutting it parallel to the horizon is called an alinucantar....

...circles through the zenith and nadir of an observer are called vertical circles. The vertical circle through the east and west points of the horizon is called the prime vertical of the observer. The vertical circle through the north and south points passes also through the poles...

...the surface of the celestial sphere. FIO. 105 SPHERICAL TRIGONOMETRY The Celestial Meridian, PВP' (Fig. 106), of an observer is the great circle in...south points coincides with the celestial meridian. Q The Ecliptic, A VВ (Fig. 107), is a great circle of the celestial sphere, apparently traversed by...

...an observer is that pole of his horizon which is exactly above his head. Vertical Circles, as NPZ8 (Fig. 106), are great circles passing through the...south points coincides with the celestial meridian. rio. 106 FIG. 107 The Ecliptic, A VB (Fig. 107), is a great circle of the celestial sphere, apparently...

...zenith and nadir. Thus the meridian passing through any place is a vertical. The prime vertical is the vertical circle passing through the east and west points of the horizon. Amplitude. — The amplitude of a celestial body is an arc of the horizon lying between the east or...

...circle for the nonagesimal point is called the DRIKSHEPA-VRITTA. * The circle of declination or the hour circle passing through the east and west points of the horizon is called UNMANDALA in Sanskrit ; but I am not acquainted with any corresponding term in English. In the treatise...