transit instrument

noun

transit instrument

an astronomical instrument, mounted on an E-W axis, in which the reticle of a telescope is always in the plane of the meridian. It is used to time the transit of a star, etc, across the meridian

First recorded in 1805–15

At that time, no original observations made at the transit instrument were ever preserved.

It is the meridian that passes through the poles and the centre of the transit instrument of the Observatory of Greenwich.

The western arm is a room of the same dimensions, intended for the transit instrument.

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

The direction of the meridian is determined either by a theodolite or a portable transit instrument.

April 19, 2024tortuous

[tawr-choo-uhs ]

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