William Optics

William Optics: astrophotography that fits in a backpack

William Optics manufactures apochromatic refractors and related optical accessories for astrophotographers. The merk is best known for the RedCat: a small, fast Petzval refractor with a flat field of view that works without a separate flattener and fits on a lightweight mount. For anyone who wants to capture the Milky Way, Andromeda, and large nebulae with a camera without a heavy setup, this is the go-to merk.

RedCat 51 and 71

The RedCat 51 WIFD (51 mm, 250 mm brand lens, f/4.9) is the travel astrograph: it’s lightweight, mounts on a star tracker, and produces point-like stars all the way to the corners of a full-frame sensor. The RedCat 71 WIFD (71 mm, 350 mm) pulls more detail out of smaller objects while still remaining portable. WIFD is the internal focuser: the tube does not change length and the balance on the mount remains the same. Which mount belongs with it is listed at the telescopes for astrophotography; a light harmonic mount or a tracker will suffice.

Flatteners and reducers for other refractors

If you already have a refractor, a flattener will flatten the field of view. William Optics makes them per model: the Flat73A for the ZenithStar 73, the Flat68III, the adjustable Flat6A III reducer and the 0.72x reducer for full frame. A reducer shortens the brand focal length and makes the optics faster; a flattener only corrects. Camera connection via the M48 adapter for Sony E Whether the M46 adapter for Canon EOS.

Visual: star diagonals and binoviewers

Also for visual inspection: the 2-inch Dura-Bright star diagonal for refractors and catadioptric telescopes, and the binoviewers with which you look at the moon and planets with two eyes. Which eyepieces fit that: eyepiece explanation.

Why William Optics at Telescoop.nl

We recommend William Optics alongside ZWO and Sky-Watcher, and advise when a RedCat is suitable and when a larger refractor or a smart telescope better fits your goal. In stock, shipping throughout Europe, in Belgium with Bancontact, 30-day return policy.

Frequently Asked Questions

RedCat 51 of 71? 51 for the Milky Way, large nebulae, and travels; 71 for galaxies and smaller nebulae if you are bringing a mount anyway.

Can I also use a RedCat visually? Yes, it has a zenith mirror and an eyepiece, but the short brand point distance makes it primarily a wide-field telescope.