William Optics Apochromatic refractor AP 108/518 UltraCat WIFD (86137)

The William Optics UltraCat108 is a state-of-the-art 108mm apochromatic refractor crafted for astrophotographers who require the highest level of optical performance. With its sophisticated 5-element Petzval design and a fast f/4.8 focal ratio, the UltraCat108 delivers stunning, edge-to-edge clarity and vibrant detail, making it ideal for capturing wide, breathtaking views of the night sky. Its solid construction, exceptional optics, and unique features set a new standard in astrophotography telescopes.

Key Features:

• Advanced 5-Element Petzval Design: Eliminates field curvature for sharp, flat images across the entire frame—no additional field flattener needed.

• 60mm Large Image Circle: Fully supports full-frame and medium-format cameras, allowing for wide-field, high-detail astrophotography—outperforming typical 106mm telescopes.

• Fast f/4.8 Optics: Provides outstanding light-gathering capability, perfect for deep-sky imaging.

• WIFD (William’s Internal Focuser Design): Patented internal focuser offers ultra-precise, stable focusing without vignetting or balance issues.

• Anti-Shrink Lens Cell Technology: Minimizes the effects of thermal expansion and contraction, keeping optics perfectly aligned in all conditions.

• Integrated Sensor Tilt Corrector: Patented design corrects sensor tilt for sharp, distortion-free images across the entire field—ideal for professional results.

• Built-In Patented Bahtinov Mask: Ensures quick and precise focusing every time, a unique feature among competing telescopes.

• Patented Handle Bar Design: Ergonomic and portable, making the telescope easy to carry and set up.

Specifications

Optics:

• Type: Apochromatic refractor

• Aperture: 108 mm

• Focal Length: 518 mm

• Focal Ratio: f/4.8

• Resolving Power: 1.28 arcseconds

• Limiting Magnitude: 12

• Light Gathering Power: 240x

• Maximum Useful Magnification: 216x

• Lens Design: 5-element Petzval (triplet front group)

• Fully Corrected Field: 60 mm

• Coating: Fully multi-coated

Tube:

• Weight: 7.8 kg

• Length: 618 mm (carrying length: 513 mm)

• Material: Aluminum

• Dew Cap Diameter: 80 mm

Focuser:

• Type: Internal (WIFD)

• Tilting Adaptor: Yes

• Camera Thread: M68, M54, M48

• Rotatable: Yes

Mount:

• Configuration: OTA (Optical Tube Assembly)

• Mounting: No mount included

• Prism Rail: Vixen-Style

Included Accessories:

• Integrated field corrector

• Dew shield

• Carry case

• Built-in Bahtinov focus mask

Applications:

• Astrophotography: Excellent

• Nebulae & Galaxies: Yes

• Moon & Planets: Yes

• Sun: Yes (with appropriate solar filter)

• Nature Observation: Not intended

Recommended For:

• Beginners: No

• Advanced users: Yes

• Observatories: No

Series: Cat