Ultra-Cat 56






Category: Refractor Telescope
We are now accepting preorders for the Ultra-Cat 56. Shipments will begin in early 2026. Your card will not be charged until the telescope is ready to ship.
Description
The William Optics Ultra-Cat 56 is a compact, wide-field astrophotography telescope designed to deliver professional imaging quality in a simple, beginner-friendly package. Its 5-element Advanced Petzval optical design produces a perfectly flat, well-corrected image circle without requiring a separate field flattener, making setup easier and reducing the number of accessories needed. With a 56 mm aperture, 269 mm focal length, and a fast f/4.8 focal ratio, the Ultra-Cat 56 captures bright, detailed images of large nebulae, star fields, and Milky Way structures, making it ideal for wide-field deep-sky imaging.
The telescope supports full-frame, APS-C, and Micro 4/3 cameras thanks to its generous 50 mm image circle, and it includes both M54 and M48 camera adapters for broad compatibility. The WIFD rack-and-pinion focuser offers precise and stable focusing with 0–30 mm of travel, and the included Sensor Tilt Xterminator helps ensure perfectly round stars across the entire frame, even when using large sensors or heavy imaging gear.
Despite its small size, the Ultra-Cat 56 is built with William Optics’ signature precision and durability. The OTA weighs 2.56 kg (5.64 lbs), with a total system weight of 3.21 kg (7.08 lbs), and the tube length ranges from 296.3 mm to 348.3 mm, making it easy to transport for travel or field use. Overall, the Ultra-Cat 56 offers a powerful combination of simplicity, optical excellence, and portability that makes it an excellent choice for both beginner and experienced astrophotographers looking for a high-performance wide-field imaging scope.
Technical Specifications
| 5 Elements Advanced Petzval Design |
| 269 mm |
| 56 mm |
| f/4.8 |
| 50 mm |
|
WIFD R&P Focuser |
| 0-30 mm |
|
Sensor Tilt Xterminator Rotator M54 Camera Adapter M48 Camera Adapter |
|
No Flattener Required |
|
Full Frame APS-C M4/3 |
| 3.21 kg / 7.08 lbs |
| 2.56 kg / 5.64 lbs |
| 296.3 mm - 348.3 mm |
Spot diagram

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Standard Shipping: Handling (business days) 0–1; Transit (business days) 7–15.
Express Shipping: Handling (business days) 0–1; Transit (business days) 7–15.
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Express Shipping · United States: $3.99
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United States · Return window (days after delivery): 30. Return method: By mail. Return postage: Seller pays.
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