WILRC51RDIII

L-RC51RDIII

William Optics

Designed for stargazing and astrophotography, the Cat 51 WIFD 51mm f/4.9 Apochromatic Refractor Telescope from William Optics uses an unorthodox design for supporting heavy cameras and delivers a wide field, a fast focal ratio, and a Petzval lens for beautiful images. The WIFD (William Optic Internal Focus Design) places the 10:1 rack-and-pinion focuser in the center of the optical tube, eliminating the tilt and vignetting that can occur from heavy cameras on traditional rear-mounted focusers. A four-element Petzval-style lens yields a sharp image with no need for a flattener and the dust cover has a built-in Bahtinov mask for tack-sharp star images. This optical tube assembly requires a mount and a tripod for use.Optical Tube Assembly Fast f/4.9 focal ratio and 250mm focal length for wide field of view and fast exposure timesApochromatic Petzval-style four-element lens produces rich views with minimal chromatic aberrationSharp image with no need for a separate field flattenerSupports 48mm image circle for full-frame, APS-C, and micro four thirds camerasDust cover with integrated Bahtinov mask allows for fine focusing on starsBuilt-in tilt adapterCamera angle rotation deviceM54 female thread for cameras, accessories, or eyepiece diagonalsFocuser William Optics Internal Focus Design places focuser in center of OTA to balance the weight of imaging systemsPrecise internal sliding of fixed optics prevents image shift, ensuring stable and clear observations10:1 coarse and fine focus rack-and-pinion designCompatible with ZWO EAF automatic focuser0-23mm focus travel, ruler to 30mmDial-style thermometer for gauging temperature effect on optical tubeUse and Handling Anodized aluminum optical tubeSturdy mounting ring and handle assembly with 210mm Vixen-style dovetailAdditional dovetail with thumbscrews on handle for guidescope or other accessory