The meridian circle is an instrument for timing of the passage of stars across the local meridian, an event known as a culmination, while at the same...

each meridian is perpendicular to all circles of latitude. A meridian is half of a great circle on Earth's surface. The length of a meridian on a modern...

0°. Together, a prime meridian and its anti-meridian (the 180th meridian in a 360°-system) form a great circle. This great circle divides a spheroid, like...

of the later meridian and Accra, Ghana. The plane of the prime meridian is parallel to the local gravity vector at the Airy transit circle (51°28′40.1″N...

The Carlsberg Meridian Telescope (formerly the Carlsberg Automatic Meridian Circle) is a decommissioned meridian circle telescope located at the Roque...

offset between the IERS Reference Meridian and the Airy transit circle is that the observations with the transit circle were based on the local vertical...

In astronomy, the meridian is the great circle passing through the celestial poles, as well as the zenith and nadir of an observer's location. Consequently...

given as either east or west. On Earth, the prime and 180th meridians form a great circle that divides the planet into the Western and Eastern Hemispheres...

the South Pole. The 100th meridian west forms a great circle with the 80th meridian east. In the United States, this meridian roughly marks the boundary...

The Tokyo Photoelectric Meridian Circle (PMC) is a meridian circle that observes and records the positions of stars and planets, which are then reported...