M9-31: OPTICAL RING SIGHT
- ID Code: m9-31
- Purpose: Show interference from an optical ring sight.
- Description: This is apparently a gizmo that is used as a sight in certain types of guns as a substitute for the crosshairs. It looks a lot like Newton's rings, but it really is a polarization phenomenon. The screen is about 6 feet away.
- Availability: Available
- References: http://www.physics.umd.edu/deptinfo/facilities/lecdem/services/refs/refsm.htm#M9-31