Revolving wooden quadrant, 1.6 meter in radius, built in 1586.
Estimated accuracy
of 32.3 seconds of arc,
based on eight reference stars.
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.