William Optics RedCat 61 WIFD APO 61mm f/4.9
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Vai al moduloWilliam Optics RedCat 61 WIFD – 61mm f/4.9 APO Refractor with Internal WIFD Focuser
The RedCat 61 WIFD is a high-precision apochromatic refractor designed for wide-field astrophotography. Built around a 4-element Petzval optical system using premium FPL-53 glass, it delivers a flat and sharp 46 mm image circle—ideal for Full Frame, APS-C, and Micro 4/3 sensors.
Its standout feature is the William Optics Internal Focus Design (WIFD): an internal rack-and-pinion focuser with a 10:1 fine focus knob, fully integrated into the optical tube. This eliminates flexure and tilt—ensuring perfect focus even with heavy imaging setups.
The focuser travel spans from 0 to 42 mm, with a scale engraved up to 50 mm, and it's fully compatible with ZWO EAF electronic focusers. An analog thermometer is also included to monitor thermal expansion effects on the tube during long exposures.
The tube is made of anodized aluminum, combining durability with lightweight performance. It comes equipped with mounting rings, a CAT handle with integrated Vixen dovetail, a top accessory rail, and a retractable dew shield featuring a built-in Bahtinov mask. Rear threads include M54 (female) and an included M48 adapter for direct camera and accessory connection.
With a focal length of 300 mm and a fast f/4.9 aperture, the RedCat 61 is perfect for capturing extended nebulae, galaxies, and wide-field Milky Way shots—even when used with lightweight mounts and star trackers. The Petzval design provides a naturally flat field—no field flattener required.
It includes a 360° camera rotator with scale markings, a tilt adapter for sensor alignment, and a padded transport case (44×23×24.5 cm) for safe storage and mobility.
Technical Specifications
- Optical Type: 4-element Petzval APO refractor
- Aperture: 61 mm
- Focal Length: 300 mm
- Focal Ratio: f/4.9
- Glass Type: FPL-53
- Image Circle: 46 mm (Full Frame compatible)
- Focuser: Internal rack-and-pinion WIFD, 10:1
- Autofocus Compatibility: ZWO EAF
- Focuser Travel: 0–42 mm (scale to 50 mm)
- Threaded Ports: M54 female + M48 adapter
- Rotator: 360° integrated with scale
- Tilt Adapter: Included
- Tube Material: Anodized aluminum
- Telescope Length: 365 mm
- OTA Weight: 2.47 kg
- Total Weight: 3.39 kg (with rings and rail)
- Carrying Case: Included (44×23×24.5 cm)
- T-Ring Compatibility: Canon EF/RF, Nikon F/Z, Sony E, Pentax K, MFT, Fuji X
- Visual Use: Possible with optional 1.25" diagonal
The RedCat 61 WIFD is a fully equipped compact refractor built for serious astrophotographers seeking top performance and portability—no additional flatteners or accessories required.