Optec Gemini Focusing Rotator
The Gemini Focusing Rotator is a super heavy-duty device, designed for some of the heaviest imaging trains out there. It makes for a perfect companion to the CDK14 telescope. Planewave itself also offers an autofocuser option in the form of a Hedrick focuser. But the mechanical and electronics quality of that focuser does not come close to that of the Gemini. Also it has no rotator option. Mounting a non-proprietary focuser always requires some extra attention to the adapters. The Gemini has an Optec-4300 connection on the telescope side and an Optec-DSI connection on the camera side. The Planewave to OPTEC-4300 Adapter allows to connect the Gemini to the telescope. If you need more backspace to cover, Optec-4300 extension adapters of different lengths can be added. On the camera-side various Optec-DSI connectors can be used to adapt to regular M68, M54 etc. or to more proprietary standards such as the Planewave Securefit connection.
The body of the focuser is made up of two machined aluminum plates and seven precise stand-off spacers. The focuser features four lead-screws and four linear bearings, a premium timing belt driven by a high torque stepper motor. Together it supports a total focus travel of 12.7mm (1/2”) with a 10kg payload capacity. The carbon fibre wrap is mostly aesthetic.
Specifications
Clear Aperture: 95mm
Minimal Back-Focus Usage: 55.9mm (full IN)
Focuser Travel: 12.7mm
Focuser Resolution: 0.11 microns per step
Rotator Resolution: 600 steps per degree
Dimensions: 239mm x 187mm
Weight: 2.9 kg
Connections
The focuser has three connections. To control the focuser and the rotator separately, there are two RJ45 jacks. A third connector is designed for a remote temperature probe.
Rotating draw tube
Most rotators are add-ons to a focuser. In the case of the Gemini, the whole draw tube rotates. The device is designed from the ground up to be used as a combined rotator and focuser.
Controller
The design includes a separate controller box that needs to find a place on the rig. I have designed a dedicated arca-compatible clamp for it and connect it to the scope using a standard arca-plate. The computer connection is via a serial RJ12 connector. An RJ12 to USB cable is included.