zenith distance

American  

noun

Astronomy.

1. the angular distance from the zenith of a point on the celestial sphere to the sphere, measured along a great circle that is perpendicular to the horizon; the complement of the altitude.

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Etymology

Origin of zenith distance

First recorded in 1695–1705

Example Sentences

He certainly found an annual variation of zenith distance, but not at the times of year required by the parallax.

From History of Astronomy by Forbes, George

The zenith distance of any point or celestial body is its angular distance from the zenith of the observer.

From Lectures in Navigation by Draper, Ernest Gallaudet

Hence, having secured the true meridian altitude of the sun, you have only to subtract it from 90� to find your zenith distance, i.e., how far you are from the sun.

From Lectures in Navigation by Draper, Ernest Gallaudet

As the distance from the horizon to the zenith is 90°, the difference, or complement of the altitude, is called the zenith distance, or co-altitude.

From Scientific American Supplement, No. 360, November 25, 1882 by Various

In this case, your distance North of the equator AD would be your zenith distance AB minus the sun's declination DB.

From Lectures in Navigation by Draper, Ernest Gallaudet