#19751 - Gemini 120 Big-Bore Focusing Rotator


In Stock: 1

Special variant of the Gemini Focusing Rotator with large 120mm (4.72”) opening. Re-designed thrust bearing allows even more light throughput and heavier loads than the original Gemini 96mm Focusing Rotator.

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.

Like all Optec focuser products, Gemini includes a remote temperature probe for automatic temperature compensation. Simply attach the temperature probe anywhere in the linear response zone of your OTA (usually the tube or truss assembly) and Gemini will automatically keep the camera package in sharp focus. The Gemini Commander software provides a convenient wizard to help determine your telescope's TC or temperature coefficient.

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.