Compass, comprises first disc with angle markings and null line and transparent second disc with direction indicator line

摘要

The disc (1) with the angle markings (3, 7) on includes a null-line (5) for the 0 deg. position. A second transparent disc (2) is rotatably secured on top of the first disc via a bearing (8) which defines a rotation axis (15) for the second disc and coincides with the midpoint (4) of the first disc where the angle markings intersect with each other. The second disc includes a straight line (10) extending from the rotation axis for indicating direction.