Astrophysics (Index)About

Danjon astrolabe

(telescope able to shift aim up/down but not horizontally)

A Danjon astrolabe is an instrument for measuring very precise horizontal coordinates of stars at precise times, sufficient information to determine precise coordinates within other celestial coordinate systems. The Danjon astrolabe's precision is accomplished through the use of a prism to split the light, in conjunction with a mercury bath to provide a precise horizontal reflective surface. It was developed by astronomer André-Louis Danjon in the 1950s as a superior successor to transit telescopes for such work. (The term astrolabe is generally used for hand-held instruments used centuries ago to make equivalent measurements.)

(telescope type)
Further reading:é-Louis_Danjon