ZENITH

, in Astronomy, the vertical point, or point in the heavens directly overhead. Or, the Zenith is a point in the surface of the sphere, from which a right line drawn through the place of any spectator, passes through the centre of the earth.

The Zenith of any place, is also the pole of the horizon, being 90 degrees distant from every point of it. And through the Zenith pass all the azimuths, or vertical circles.

The point diametrically opposite to the Zenith, is called the nadir, being the point in the sphere directly under our feet: and it is the Zenith to our antipodes, as our Zenith is their nadir.

Zenith-Distance, is the distance of the sun or star from our Zenith; and is the complement of the altitude, or what it wants of 90 degrees.