Gemini Focusing Rotator Gemini Focusing Rotator

Low-Profile Focusing Rotator System

Optec engineers have developed a completely new concept for combining telescope focus and camera rotation functions into a single robust, yet compact package.  Rather than simply adding a rotator onto the end of a focuser drawtube, Gemini was designed from inception with a rotating drawtube providing superior strength and rigidity for heavy camera payloads.  Featuring four lead-screws and four linear bearings, Gemini can easily handle 10-kg. (22-lbs.) payload packages without flexure.  Full 360-degree rotation is a built-in function of the Gemini with a full 1/2" of linear travel.  At the center of travel, Gemini measures a mere 2.5" in thickness. 

Robust Compact Design

To maintain a flat, rigid base for heavy camera packages, Gemini's shell consists of two parallel plates machined from MIC-6 tool plate providing flatness within 0.001" (25 microns).  Seven precise stand-off spacers maintain the 2.25" separation of these plates.  The rotating drawtube is moved linearly with 1/2" of total travel using a premium timing belt driven by a high torque stepper motor.  The entire package is accented with a beautiful carbon fiber wrap.  Dual RJ45 connectors provide connection to the Gemini Control hub.  The independent rotating drawtube is supported by a custom X-cage bearing system supported by large, 6mm chrome ball bearings. 

Support for Multiple Telescopes

Featuring identical OPTEC-4300 mechanical interfaces front and back, the Gemini can be easily fitted to most any large telescope OTA.  Recessed oval point setscrews provide three-point direct contact with the heavy wall OPTEC-4300 dovetail mount.  Gemini's clear aperture of 3.75" is maintained through each adapter, passing even large light cones through to the camera image plane without vignetting.

On the camera side, a typical configuration might include a 4300 receiver for the Optec-DSI 3.5 High Performance spacer sets configurable to 1/4" increments when additional spacing is needed. 

Currently designed telescope adapters include support for the AG Optical iDK's, Ceravolo Optical Systems Astrographs, Meade and Celestron 10-inch and larger class SCT, and Plane Wave Secure-Fit. 

Customer Images:

Charles Miller supplied this Veil image taken through his new Gemini focusing rotator mounted to his 12" Meade LX850 OTA.  Charlie took delivery of his Gemini in May 2015.

"In the attached image of the Veil Nebula, the imaging run was about 4 hours and the temperature dropped about 10 C. The image consists of 48 subs of 5 minutes; 16 each in unbinned RGB. I was very pleased to see how well the Gemini's TC held the focus during the entire four hours. Congrats on a great product!"

Image courtesy Charles Miller - August 2015.

OPTEC-4300 4.3-inch Adapters

The new OPTEC-4300 standard dovetail mounting system is being developed quickly to support a large stable mounting connection between telescope and camera. 

Click the button at right for a full selection of both telescope-side and camera-side OPTEC-4300 adapters. 

For other telescope OTA's,  PreciseParts can supply additional custom adapters while the larger OPTEC-4300 adapter line is developed and expanded. 

More Information and Ordering Information

For additional details and ordering information, click the Gemini button at right or click here.

Stock #19750 - Gemini Focusing Rotator.