A riflescope comprising: a first, main housing, an objective group comprising at least one objective lens that directs light toward a first image plane, the objective group disposed toward an objective end of the main housing; a first reticle comprising at least one physical reticle mark, characterized in that the first reticle disposed in or near the first image plane comprises at least one marker (45, 48) that is not visible to an operator of the riflescope during normal use of the riflescope; and a detachable digital ocular group comprising: (a) a second housing attachable to and detachable from an ocular end of the main housing; (b) an image sensor disposed at a second image plane; (c) at least one processor, wherein the at least one marker (45, 48) is detectable by the at least one processor through the image sensor; (d) a digital display; (e) a power supply for powering at least one of the at least one processor and the digital display; and (f) wherein the image sensor is configured to receive an image representative of light that has entered the objective end of the main housing, wherein the processor is configured to process the image received by the image sensor and to display an image representative of the received light on the digital display, and wherein the processor is programmed to digitally overlay the at least one physical reticle mark with one or more secondary aiming marks (51, 53, 55) at the second image plane. a first, main housing, an objective group comprising at least one objective lens that directs light toward a first image plane, the objective group disposed toward an objective end of the main housing; a first reticle comprising at least one physical reticle mark, characterized in that the first reticle disposed in or near the first image plane comprises at least one marker (45, 48) that is not visible to an operator of the riflescope during normal use of the riflescope; and a detachable digital ocular group comprising: (a) a second housing attachable to and detachable from an ocular end of the main housing; (b) an image sensor disposed at a second image plane; (c) at least one processor, wherein the at least one marker (45, 48) is detectable by the at least one processor through the image sensor; (d) a digital display; (e) a power supply for powering at least one of the at least one processor and the digital display; and (f) wherein the image sensor is configured to receive an image representative of light that has entered the objective end of the main housing, wherein the processor is configured to process the image received by the image sensor and to display an image representative of the received light on the digital display, and wherein the processor is programmed to digitally overlay the at least one physical reticle mark with one or more secondary aiming marks (51, 53, 55) at the second image plane. (a) a second housing attachable to and detachable from an ocular end of the main housing; (b) an image sensor disposed at a second image plane; (c) at least one processor, wherein the at least one marker (45, 48) is detectable by the at least one processor through the image sensor; (d) a digital display; (e) a power supply for powering at least one of the at least one processor and the digital display; and (f) wherein the image sensor is configured to receive an image representative of light that has entered the objective end of the main housing, wherein the processor is configured to process the image received by the image sensor and to display an image representative of the received light on the digital display, and wherein the processor is programmed to digitally overlay the at least one physical reticle mark with one or more secondary aiming marks (51, 53, 55) at the second image plane.