Surveying Instrument and Sundial, by Christoph Trechsler, Dresden?, 1608

This type of instrument is shown in contemporary texts placed at the edge of a plane table. Compass plate with index arm fixed on decorative wooden base. Two folding sights mounted on base. One sight has crossed threads, the other is a pinhole. Vertical semicircle with string-gnomon dial on one side (the construction points for the graduation of the dial are visible and arranged in a square pattern). On the other side semicircle of degrees and shadow square with alidade.