William Optics RedCat 61 WIFD

A 61mm f/4.9 Petzval-like Optical System

The heart of the RedCat 61 is its 61mm Petzval-like optical design, which produces a flat field of view without needing an additional flattener. At a fast focal ratio of f/4.9, you can capture significant detail on faint nebulae and galaxies with shorter exposure times, reducing tracking demands on your mount. This integrated design ensures sharp, pinpoint stars from the center to the corners of your frame.

William Optics WIFD: A Zero-Flexure Internal Focuser

This RedCat model incorporates the William Optics Internal Focus Design (WIFD), a major upgrade for imagers. Unlike traditional focusers that move the camera and can introduce sag or tilt, the WIFD moves the optics internally. This mechanism provides exceptionally fine control and ensures the imaging train remains perfectly rigid and orthogonal to the focal plane, even when loaded with heavy cameras and filter wheels.

M48 Direct-Connect: Imaging Without Backfocus Spacing

One of the most significant advantages of the RedCat 61 is its simplicity. The Petzval design eliminates the need to calculate and set a precise backfocus distance. You simply attach your DSLR, mirrorless, or dedicated astronomy camera to the included M48 adapter, focus, and start imaging. This removes a common point of failure and frustration from the astrophotography process, getting you to a successful result faster.

Integrated Mounting: The 2-in-1 Vixen/Arca Plate

The RedCat 61 is built for the field. It features a CNC-machined tube ring connected to a dual-style mounting plate compatible with both Vixen-style saddles and Arca-Swiss tripod heads out of the box. An integrated handle bar makes transport easy and doubles as a mounting point for a guide scope. The entire package fits into a custom soft carry case, making it an ideal grab-and-go imaging instrument.

RedCat 61 vs. RedCat 51: 10mm More Aperture for Deeper Views

While both astrographs share the same f/4.9 Petzval design and legendary ease of use, the RedCat 61 offers a distinct advantage in light-gathering power and image scale over its 51mm sibling.

• RedCat 51 Advantage: The RedCat 51 offers a wider true field of view, making it better suited for capturing immense targets like the entire North America Nebula (NGC 7000) or the full expanse of the Rho Ophiuchi cloud complex in a single frame.
• RedCat 61 Advantage: With a 61mm aperture, the RedCat 61 gathers nearly 44% more light, allowing for deeper images or shorter total integration times. Its longer focal length provides a tighter field of view, which is ideal for framing medium-sized targets like the Andromeda Galaxy (M31) or the Pleiades (M45) with more resolution and impact.