Tycho's 1585 Great Equatorial Armillary

Great equatorial armillary, 3 meters in diameter. Built in 1585, this is an armillary sphere reduced to its bare essentials, and one of Tycho's workhorse instrument. Estimated accuracy of 38.6 seconds of arc.

Bibliography:

Thoren, V.E. 1973, Journal for the History of Astronomy, 4, 25.

Wesley, W.G. 1978, Journal for the History of Astronomy, 9, 42.

Tycho