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Product Description
If you're in search of top-tier imaging performance, this William Optics Ultra-Cat 76 is the telescope for you. With 5 internal lens elements composed of high quality glass, you can expect stunningly sharp, well-corrected astrophotos! As a Petzval refractor, there is no need for an additional field flattener nor backspace calculation, making camera attachment a breeze. Stars will be sharp across the entire field of view, even for medium-format and full frame cameras! Thanks to the innovation from William Optics, this Ultra-Cat 76 APO Refractor is sure to take your astrophotography to the next level.
The 76 mm aperture paired with the 365 mm focal length results in a focal ratio of f/4.8, making this a speedy system for deep space imaging. Featuring an incredibly large image circle of 50 mm, the William Optics Ultra-Cat 76 supports medium-format and full frame cameras for stunning wide field images. In addition to these superior optics, this APO telescope comes furnished with the William Optics Internal Focus Design (WIFD) for smooth, stable focusing. You even have the ability to attach an electronic autofocuser (not included) to this telescope for automatic, hands-free focusing. With features like these, the William Optics Ultra-Cat 76 is the ultimate tool for astrophotographers eager to capture breathtaking images of our universe.
Key Features
- Advanced 5-Element Petzval Optics: Eliminates field curvature, ensuring sharp, edge-to-edge stars without additional flatteners.
- 50mm Large Image Circle: Fully supports Full Frame cameras, APS-C and M4/3 sensors for optimal performance. Compatible with Medium Format.
- Fast f/4.8 Optics: Superior light-gathering capability, enabling deep-sky imaging with shorter exposure times.
- WIFD (William’s Internal Focuser Design): Patented internal rack-and-pinion focuser ensures stable and precise focusing. No vignetting or balance issues — ideal for astrophotography. Compatible with EAF (Electronic Automatic Focuser) for precision focus control.
- Sensor Tilt Xterminator (STX) & Rotator: Integrated tilt adjuster eliminates sensor misalignment, ensuring uniform image sharpness.
- No Flattener Required: The optical design naturally corrects field curvature, simplifying setup.
- Anti-Shrink Lens Cell Technology: Reduces thermal expansion effects, maintaining perfect optical alignment in any climate.
- Patented Bahtinov Mask for Focusing: Built-in focusing aid ensures pinpoint star sharpness with ease.
- Premium Build & Ergonomic Design: Lightweight yet robust (4.31 kg / 9.5 lbs) construction with a sleek anodized finish. Patented handle bar design for enhanced portability and ease of use.
- Versatile Camera Compatibility: Supports Canon EF, RF, Nikon F,Z, Sony E, Pentax K, MFT, and FUJI X mounts.
Included Sensor Tilt Xterminator (STX)
The STX builds upon the foundation of traditional sensor tilt adjusters, offering a streamlined and intuitive design that eliminates the need for cumbersome disassembly. Unlike conventional systems that require camera removal for tilt correction, the STX allows adjustments to be made directly from the side of the assembly, significantly reducing setup time and enhancing ease of use.
By refining the original 4 pull-in and 8 push-out screw configuration into a more efficient 4 push-out and 4 locked screw system, the STX enables precise and controlled adjustments. Operating like a seesaw mechanism, the system allows for effortless corrections—simply loosen one screw and tighten the opposite diagonal screw to achieve fine tilt alignment. This ensures that astrophotographers can make on-the-fly refinements without disrupting their imaging workflow, maintaining pinpoint star performance across the entire frame.
What's in the Box
Specifications
| Design: | 5-Element Advanced Petzval |
| Lens Elements: | 2x Super ED Glass 1x ED Glass 1x Lanthanum Glass 1x X-Element |
| Focal Length: | 365mm |
| Diameter: | 76mm |
| Aperture: | f/4.8 |
| Focuser: | WIFD (WilliamOptics Internal Focus Design) Note: Compatible with EAF |
| Image Circle: | 50mm >Full Frame |
| Tube Length: | 363mm-415mm |
| Tube Weight: | 3.81kg / 8.4lbs |
| Total Weight: | 4.98kg / 10.98lbs |
| Adapters Included: | Sensor Tilt Xterminator Rotator M54/M48 Camera Adapters |
| T-Mounts Supported: | Canon EF/RF Nikon F/Z Sony E Pentax K MFT (M4/3) FUJI X |
| Camera Formats Supported: | Medium Format (Compatible) Full Frame (Recommended) APS-C M4/3 |
Spot Diagram
What can I see with a William Optics Ultra-Cat 76 WFID APO Petzval OTA (L-UC76)?
Here are some simulated views of common objects. Results with your telescope will vary with viewing conditions, obrits, equipment and more.
Jupiter with
25mm Eyepiece - 15x Magnification
(Sold Separately)
Jupiter with
10mm Eyepiece - 37x Magnification
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Jupiter with
5mm Eyepiece - 73x Magnification
Sold Separately
Moon with 25mm Eyepiece
15x Magnification
(Sold Separately)
Moon with 10mm Eyepiece
37x Magnification
Sold Separately
Moon with 5mm Eyepiece
73x Magnification
Sold Separately
Andromeda with 36mm Eyepiece
10x Magnification
Sold Separately
Andromeda with 25mm Eyepiece
15x Magnification
(Sold Separately)
Andromeda with 10mm Eyepiece
37x Magnification
Sold Separately
