Horizontal Compass Dial (17th Century)
Early 17th century, France
For orientation, a tiny compass is set in a covered box at the edge of this round dial. Hours are marked near the rim, a perpetual calendar and phases of the moon on the inner circles. The back has a sighting rule and scales of degrees to find the time of night by observing positions of certain stars.
AMNH Hayden Planetarium Collection 2049