The Ultra-Cat 76 is a high-performance 76mm apochromatic refractor, designed for astrophotographers who demand exceptional clarity and true color accuracy.

With a 5-element advanced Petzval optical design, including super ED and lanthanum glass, and a fast f/4.8 focal ratio, this telescope delivers stunningly sharp, flat-field images across its 50mm image circle. Optimized for Full Frame, APS-C, and M4/3 sensors, it also offers compatibility with Medium Format cameras for outstanding wide-field astrophotography.

William Optics Ultra-Cat 76

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.

Note:

Astrophotography Only
This telescope is specifically designed for astrophotography, and its optical design does not support visual observation.

Lens Type 5-Element Advanced Petzval
Lens Elements Super ED Glass x2 ED Glass x1 Lanthanum Glass x1 X-Element x1
Focal Length 365 mm
Diameter 76 mm
Focal Ratio f/4.8
Image Circle 50 mm
Focuser WIFD R&P Focuser Compatible with EAF
Focuser Travel 0-20 mm (Ruler to 21mm)
Adapter Included Sensor Tilt Xterminator Rotator M54, M48 Camera Adapters
Optional Flattener No Flattener Required
T-Mount Support Canon EF, RF Nikon F, Z Sony E Pentax K MFT (M4/3) FUJI X
Camera Format Full Frame APS-C M4/3
Dovetail Type Vixen ↔︎ Arca-Swiss
Tube Length 363 mm – 415 mm
OTA Weight 3.81 kg / 8.4 lbs
Total Weight 4.98 kg / 10.98 lbs
  • Main Tube
  • Bahtinov Cap
  • M48, M54 Adapter with Wrench
  • Dual-side Plate
  • Mounting Ring & Handle bar
  • Riser Blocks
  • Soft Carry Case
  • Allen Key Set

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William Optics Ultra-Cat 76

SKU: WO-T-C-76BR

$3,789.00

Available on back-order

✅ Fast Shipping & Tracking
✅ Stocked in Melbourne, Australia
✅ Expert Advice
✅ Lifetime Technical Support

    Need Expert Advice?

    Visual Astronomy, Astrophotography, Microscopy and Macro Photography can be a little complicated sometimes as there are a lot of options. If you'd like to check something before you purchase just let us know and we'd be happy to help!

    Enquire now or call us (03) 9042 2293

    William Optics Ultra-Cat 76

    SKU: WO-T-C-76BR

    $3,789.00

    Available on back-order

    The Ultra-Cat 76 is a high-performance 76mm apochromatic refractor, designed for astrophotographers who demand exceptional clarity and true color accuracy.

    With a 5-element advanced Petzval optical design, including super ED and lanthanum glass, and a fast f/4.8 focal ratio, this telescope delivers stunningly sharp, flat-field images across its 50mm image circle. Optimized for Full Frame, APS-C, and M4/3 sensors, it also offers compatibility with Medium Format cameras for outstanding wide-field astrophotography.

    William Optics Ultra-Cat 76

    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.

    Note:

    Astrophotography Only
    This telescope is specifically designed for astrophotography, and its optical design does not support visual observation.

    Lens Type 5-Element Advanced Petzval
    Lens Elements Super ED Glass x2 ED Glass x1 Lanthanum Glass x1 X-Element x1
    Focal Length 365 mm
    Diameter 76 mm
    Focal Ratio f/4.8
    Image Circle 50 mm
    Focuser WIFD R&P Focuser Compatible with EAF
    Focuser Travel 0-20 mm (Ruler to 21mm)
    Adapter Included Sensor Tilt Xterminator Rotator M54, M48 Camera Adapters
    Optional Flattener No Flattener Required
    T-Mount Support Canon EF, RF Nikon F, Z Sony E Pentax K MFT (M4/3) FUJI X
    Camera Format Full Frame APS-C M4/3
    Dovetail Type Vixen ↔︎ Arca-Swiss
    Tube Length 363 mm – 415 mm
    OTA Weight 3.81 kg / 8.4 lbs
    Total Weight 4.98 kg / 10.98 lbs
    • Main Tube
    • Bahtinov Cap
    • M48, M54 Adapter with Wrench
    • Dual-side Plate
    • Mounting Ring & Handle bar
    • Riser Blocks
    • Soft Carry Case
    • Allen Key Set

    Reviews

    There are no reviews yet.

    Be the first to review “William Optics Ultra-Cat 76”

    Your email address will not be published. Required fields are marked *

      Need Expert Advice?

      Visual Astronomy, Astrophotography, Microscopy and Macro Photography can be a little complicated sometimes as there are a lot of options. If you'd like to check something before you purchase just let us know and we'd be happy to help!

      Enquire now or call us (03) 9042 2293