The Ultra-Cat 108 is a superb telescope that’s ideal for those seeking top-of-the-line imaging results. Its 5 internal glass elements deliver exceptional clarity and detail. Its large 108mm (4.25”) aperture provides ample light for outstanding detail and contrasts. The Ultra-Cat 108 refractor features a Petzval design, which eliminates the need for additional backspace calculation and field flattener. Its large 108mm aperture allows you to capture stellar images even with full-frame and medium-format cameras. William Optics' innovative Ultra-Cat 108 APO refractor is a must-have for astrophotographers. Its 518-mm focal length and 108mm aperture allow you to take amazing deep space photos. The Ultra-Cat 108 features a 60mm image circle, which makes it ideal for shooting with medium and full-frame cameras. In addition to its superior optics, this telescope also comes with William Optics' Internal Focus Design, which ensures stable focusing.

• Lens Type: Petzval Design
• Focal Length: 518mm
• Aperture: 108mm
• Focal Ratio: f/4.8
• Image Circle 60mm up to Medium Format
• Flattener: 5 Element Petzval
• Focuser: WIFD Internal Focus Design, Compatible with EAF
• Lens Material: Super ED Glass x2 ED Glass x1 Lanthanum Glass x1 X-Element x1
• Camera Format Compatibility: Medium Format Full Frame APS-C M4/3
• T-Mounts Supported: Canon EF, RF, NIkon F, Z, Sony E, Pentax K, Micro Four Thirds, FUJI X
• Tube Length: 510.5-588.5mm
• OTA Weight: 17.53 lbs.

• In addition to having five lens elements, the William Optics Ultra-Cat 108 features two Super ED glass elements and one ED lens.
• These components eliminate various aberrations, including field curvature and coma, resulting in exceptional clarity and color correction.
• Its 60mm image circle is supported by both full-frame and medium-format cameras, and it features an edge-to-edge sharpness. These exceptional optics allow you to easily view the stunning structure of galaxies and the detail of star clusters. William Optics' 5-lens ultra-cat refractor is ideal for astrophotography.
• It features a sophisticated design and is capable of delivering exceptional images. Its built-in focuser ensures high-quality images. In addition, the company's internal focus design allows you to use the device with a steady and solid mount.
• The Ultra-Cat 108 from William Optics is a must-have for astrophotographers who want to capture stellar images.
• Its 518-mm focal length allows you to fill the frame with different objects, such as the Open Star Cluster and the Orion Nebula. Besides having a large 108mm aperture, the Ultra-Cat 108 also features a fast f/4.8 focal ratio that allows you to capture plenty of light in a short time. 
• In addition, two adapters are included in this package, which will allow you to seamlessly integrate the device into your imaging training. The Ultra-Cat 108 features an internal focuser that enables you to focus on the objects in your imaging train without moving the whole body.
• This feature eliminates the possibility of draw-tube sag and provides you with better image quality. It also helps minimize the risk of vignetting, which is typically associated with using heavier equipment.