An optical scope with a position-based on/off switch preserves power by automatically deactivating one or more electrical components when the scope is not in use. The scope includes an orientation sensor that determines when the scope is in an inactive position by sensing when the scope is rolled left or right to a predetermined angle of inclination from an upright position. A power switch receives an indicia of orientation from the orientation sensor and deactivates the one or more electrical components when the scope is in the inactive position, thus preserving power and extending the life of a battery.