Abstract: A clamping device for coupling optical devices in coaxial, tandem alignment includes a front clamp assembly that has elastically deformable split collar halves tightenable onto a front optical device by a screw tightenable into bores disposed transversely through a pair of arms extending radially from the split collar halves. A rear optical device support protrudes rearward from the front clamp assembly, and has a releasable fastener such as a screw or dovetail joint for supporting a rear optical device in coaxial alignment with the front optical device. Preferably, the arm is mounted to the front clamp assembly by means of a pivotable joint which is latchable in a first, rearward position, and a second, forward position in which the rear optical device is positioned along the side of the front optical device, so that the front device may be used independently of the rear device.