Abstract: An actuating device for setting an optical parameter of an optical device including a telescopic sight. The actuating device includes a first coupling part rotatable about a rotation axis and an index element pushable onto the first coupling part for assuming an operating position. A guide arrangement guides the index element on the first coupling part and is configured to permit a push-on of the index element in the direction of the rotation axis and to permit a twisting of the index element relative to the first coupling part at least in a direction perpendicular to or tangential to the rotation axis. A second coupling part is configured to provide friction forces counteracting a twisting of the index element relative to the first and second coupling parts when the index element is in the operating position thereof.

Abstract: An actuating device for setting an optical parameter of an optical device including a telescopic sight. The actuating device includes a first coupling part rotatable about a rotation axis and an index element pushable onto the first coupling part for assuming an operating position. A guide arrangement guides the index element on the first coupling part and is configured to permit a push-on of the index element in the direction of the rotation axis and to permit a twisting of the index element relative to the first coupling part at least in a direction perpendicular to or tangential to the rotation axis. A second coupling part is configured to provide friction forces counteracting a twisting of the index element relative to the first and second coupling parts when the index element is in the operating position thereof.