meridian transit

Observation of meridian transits was once very important for timekeeping purposes (see transit instrument).

He championed the method of determining the longitude of surface features using their central meridian transit.

The east wing contains an intact meridian transit telescope and sidereal pendulum clock.

Due to Mercury's 3:2 spin-orbit resonance, a solar day (the length between two meridian transits of the Sun) lasts about 176 Earth days.

Until the age of satellite navigation ships usually took sights at dawn, during the forenoon, at noon (meridian transit of the Sun) and dusk.

Once good star catalogs were available a transit telescope could be used anywhere in the world to accurately measure local longitude and time by observing local meridian transit times of catalogue stars.

The telescope was then brought into the meridian by repeatedly timing the (apparent, incorrect) upper and lower meridian transits of a circumpolar star and adjusting one of the bearings horizontally until the interval between the transits was equal.

Groombridge Transit Circle was a meridian transit circle made by Edward Troughton for Stephen Groombridge in 1806, which Groombridge used to compile data for the star catalogue, Catalogue of Circumpolar Stars.

The making of circles was shortly afterwards taken up by Edward Troughton, who in 1806 constructed the first modern transit circle for Groombridge's observatory at Blackheath, the Groombridge Transit Circle (a meridian transit circle).

Originally built in 1906, but later demolished in 1966 then rebuilt in 1997, the station includes several modes of transportation including the Meridian Transit System, Amtrak, Norfolk Southern rail corridor, Greyhound buses, Trailways and other providers of transit services.

In the late 10th century, a huge observatory was built near Tehran, Iran, by the astronomer Abu-Mahmud al-Khujandi who observed a series of meridian transits of the Sun, which allowed him to calculate the tilt of the Earth's axis relative to the Sun.