The great brass sextant of Johannes Hevelius, portrayed here observing with his second wife Elisabetha. Six feet in radius, this instrument was closely modeled on Tycho's great sextant .
Hevelius' azimuthal quadrant. An ingenious system of counterweights allowed a single observed to manipulate the instrument while taking readings.
Hoskin, M. 1997, The Cambridge Illustrated History of Astronomy .
-Written and last revised 12 November 1998 by paulchar@ucar.edu.