prime vertical

noun

1. astronomy the great circle passing through the observer's zenith and meeting the horizon due east and west

Example Sentences

The amplitude of a star is its distance from the prime vertical, measured on the horizon, north or south.

From Project Gutenberg

The imaginary circle which passes immediately over your head as you face the South is called the Prime Vertical.

From Project Gutenberg

The transit instrument is also used in the prime vertical for the determination of latitudes.

From Project Gutenberg

Take the morning sight for longitude when the sun is on or as near as possible to the prime vertical.

From Project Gutenberg

The prime vertical is that vertical circle which passes through the east and west points.

From Project Gutenberg