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.
Thoren, V.E. 1973, Journal for the History of Astronomy, 4, 25.
Wesley, W.G. 1978, Journal for the History of Astronomy, 9, 42.
-Written and last revised 8 November 1998 by paulchar@ucar.edu.