Gemini Focusing Rotator
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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 2.45" 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 2.2" 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.
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.
"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.