# zenith

(redirected from*Astronomy zenith*)

Also found in: Dictionary, Thesaurus.

## zenith,

in astronomy, the point in the sky directly overhead; more precisely, it is the point at which the celestial sphere**celestial sphere,**

imaginary sphere of infinite radius with the earth at its center. It is used for describing the positions and motions of stars and other objects. For these purposes, any astronomical object can be thought of as being located at the point where the line of sight

**.....**Click the link for more information. is intersected by an upward extension of a plumb line from the observer's location. Its position in the sky thus depends on the direction of the earth's gravitational field at the observer's location. The zenith is a reference point in the altazimuth coordinate system

**altazimuth coordinate system**

or

**horizon coordinate system,**

astronomical coordinate system in which the position of a body on the celestial sphere is described relative to an observer's celestial horizon and zenith.

**.....**Click the link for more information. ; its altitude above the celestial horizon is 90°. The angular distance from the zenith to a celestial body is called the zenith distance. The nadir, directly opposite the zenith, has a zenith distance of 180°; the celestial horizon has a zenith distance of 90°.

The Columbia Electronic Encyclopedia™ Copyright © 2013, Columbia University Press. Licensed from Columbia University Press. All rights reserved. www.cc.columbia.edu/cu/cup/

## Zenith

(religion, spiritualism, and occult)The zenith is the point in the heavens directly overhead at any given location on Earth. It should be carefully distinguished from the midheaven (with which it is often confused).

The Astrology Book, Second Edition © 2003 Visible Ink Press®. All rights reserved.

## What does it mean when you dream about a zenith?

May indicate aspiration and culmination of achievement in the world.

The Dream Encyclopedia, Second Edition © 2009 Visible Ink Press®. All rights reserved.

## zenith

[′zē·nəth] (astronomy)

That point of the celestial sphere vertically overhead.

McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.

## zenith

The point on a celestial sphere directly overhead the observer. It is called the

*observer's zenith*. An*astronomical zenith*is where an imaginary plumb line through the observer and the center of the earth intersects the celestial sphere. A*geographical zenith*is where a line perpendicular to smooth earth intersects the celestial sphere. These terms, however, are not synonymous. The point 180° from the zenith is called the*nadir*.An Illustrated Dictionary of Aviation Copyright © 2005 by The McGraw-Hill Companies, Inc. All rights reserved

## zenith

*Astronomy*the point on the celestial sphere vertically above an observer

Collins Discovery Encyclopedia, 1st edition © HarperCollins Publishers 2005