An electronic indicator on a see-through optical scope indicates whether an optical system is canted. The indicator may include illuminable visual indicators positioned on opposite sides of a field of view through the optical scope. The indicator may be visual, haptic, or aural. The visual indicator may include one or more LEDs positioned on the periphery of the field of view, and may be optically coupled to an appropriate position on the face of the reticle using a suitable waveguide. The LEDs are coupled to a microprocessor which is, in turn, coupled to a solid-state electronic inclinometer that is incorporated into the internal structure of the optical system. The microprocessor is configured to selectively illuminate one or more of the visual indicators based on the output of the inclinometer, thereby indicating how the reticle is canted, if at all.