star and sundial, Dutch, 1681

Combined star and sun (altitude) dial, signed Anthony Sneewins, Delft, Holland, dated 1681.

Dated 1681, this astronomical instrument is believed to be a joint star and sundial for finding local time. Anthony Sneewins, an instrument maker from Delft in Holland, made this dial. This view of the device shows the sundial part of the instrument that indicates equal hours. In use the instrument is held vertically by the ring and rotated until the Sun can be aligned with the moving sighting vane. The position of the vane gives an indication of the Sun's altitude and hence local solar time. This instrument is transitional from the traditional astrolabe that was disappearing in Western Europe and being replaced by instruments such as the ring dial and horary quadrant.