{"product_id":"william-optics-ultracat-108-f-4-8-wifd","title":"William Optics UltraCat 108 f\/4.8 WIFD","description":"\u003cul class=\"DAV-feature-list\"\u003e\n\u003cli\u003e108mm Aperture, 5-Element Advanced Petzval Optical Design\u003c\/li\u003e\n\u003cli\u003eFast f\/4.8 Focal Ratio with 518mm Focal Length\u003c\/li\u003e\n\u003cli\u003eMassive 60mm Flat-Field Image Circle\u003c\/li\u003e\n\u003cli\u003ePatented William Optics Internal Focuser Design (WIFD)\u003c\/li\u003e\n\u003cli\u003eSupports Medium Format, Full Frame, and APS-C Sensors\u003c\/li\u003e\n\u003cli\u003e7.96 kg Optical Tube Assembly Weight\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c!-- more --\u003e\n\u003cul class=\"tabs\"\u003e\n\u003cli class=\"active\"\u003eDescription\u003c\/li\u003e\n\u003cli\u003eFAQ\u003c\/li\u003e\n\u003cli\u003eSpecifications\u003c\/li\u003e\n\u003cli\u003eIn the Box\u003c\/li\u003e\n\u003cli\u003eWarranty\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cul class=\"tabs-content\"\u003e\n\u003cli class=\"active\"\u003e\n\u003cdiv\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section-center\"\u003e\n\u003ch2\u003eWilliam Optics UltraCat 108 f\/4.8 WIFD\u003c\/h2\u003e\n\u003cp\u003eThe William Optics UltraCat 108 f\/4.8 WIFD integrates a 108mm, 5-element Petzval optical system to deliver a massive 60mm flat image circle at a fast f\/4.8 focal ratio. With a 518mm focal length and an OTA weight of just 7.96 kg, this astrograph is engineered for demanding imagers using full-frame and medium format cameras. The innovative internal focuser provides 30mm of precise travel, ensuring perfect focus without altering the telescope's 512.9mm minimum tube length or balance.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003e5-Element Petzval Optics: A Flat 60mm Image Circle at f\/4.8\u003c\/h3\u003e\n\u003cp\u003eThe UltraCat 108's optical core is an advanced 5-element Petzval design that requires no additional field flattener. This integrated system uses a combination of two Super ED, one ED, one Lanthanum, and one X-Element glass to produce a perfectly flat 60mm image circle, ensuring pinpoint stars from the center to the corners of even medium-format sensors. At f\/4.8, you can capture deep signal on faint nebulae and galaxies with shorter exposure times.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003ePatented WIFD Focuser: 30mm of Stable, Internal Travel\u003c\/h3\u003e\n\u003cp\u003eWilliam Optics' patented Internal Focuser Design (WIFD) eliminates the primary weakness of traditional refractors: focuser sag and balance shift. By moving the optical elements internally over a 30mm travel distance, the camera and imaging train remain fixed. This rock-solid connection prevents tilt and flexure, maintaining perfect orthogonality to the image plane, which is critical for achieving sharpness across the large 60mm field. The focuser is also compatible with electronic focusers like the ZWO EAF for automated imaging routines.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003e7.96 kg OTA with Integrated Rotator and Tilt Adjuster\u003c\/h3\u003e\n\u003cp\u003eWeighing only 7.96 kg, the UltraCat 108 OTA is remarkably portable for its aperture and capabilities, making it compatible with a wide range of mid-to-heavy-payload equatorial mounts. The system includes professional-grade tools for perfect camera alignment right out of the box. An integrated camera rotator allows for effortless framing of your target, while the included Sensor Tilt Xterminator gives you fine control to eliminate any residual tilt in your imaging train.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eM48, M54, and M68 Adapters for Medium Format to M4\/3 Sensors\u003c\/h3\u003e\n\u003cp\u003eThe UltraCat 108 is designed for immediate integration into your existing setup. It ships with a comprehensive set of M48, M54, and M68 camera adapters, accommodating everything from standard 2\" filter wheels to large-format cameras. This ensures a wide, unvignetted light path to capitalize on the full 60mm image circle. The system also supports a wide range of T-mounts for Canon, Nikon, Sony, Pentax, MFT, and Fuji cameras, offering versatility for both dedicated astro cameras and DSLRs\/mirrorless bodies.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-bg-light\"\u003e\n\u003cdiv class=\"DAV-section\"\u003e\n\u003ch3\u003eUltraCat 108 vs. Takahashi FSQ-106EDX4: Aperture and Inclusions\u003c\/h3\u003e\n\u003cp\u003eThe Takahashi FSQ-106EDX4 is an industry benchmark, known for its impeccable optical quality and the ability to achieve a massive 88mm image circle with its dedicated reducer. It sets a high standard for flat-field performance.\u003c\/p\u003e\n\u003cp\u003eThe William Optics UltraCat 108 presents a compelling alternative focused on aperture and out-of-the-box functionality. It offers a larger 108mm aperture and a slightly faster native f\/4.8 focal ratio. Crucially, the UltraCat 108 includes a rotator, tilt adapter, multiple camera adapters, mounting rings, and a carrying case as standard, components that are often costly add-ons for other premium systems. This makes the UltraCat 108 a complete, ready-to-image package for the advanced astrophotographer seeking exceptional value and capability.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eDoes the William Optics UltraCat 108 require a field flattener?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eNo. The UltraCat 108 uses a 5-element Petzval optical design, which has a built-in field flattener. It is engineered to deliver a flat 60mm image circle with no additional optical correctors required.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat is the advantage of the WIFD focuser on the UltraCat 108?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe William Optics Internal Focuser Design (WIFD) moves optical elements internally to achieve focus, rather than moving the camera externally. This offers two key advantages:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eNo Sag or Flexure:\u003c\/strong\u003e Your camera and filter wheel are attached to a solid, fixed point, eliminating sag that can cause tilted images.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eStable Balance:\u003c\/strong\u003e Since the heavy imaging payload doesn't move, the telescope's balance on the mount remains constant throughout the 30mm of focus travel.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eHow does the UltraCat 108's 60mm image circle benefit imaging the Andromeda Galaxy (M31) with a full-frame camera?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eA full-frame sensor has a diagonal of approximately 43mm. The UltraCat 108's massive 60mm image circle completely illuminates this sensor with high-quality, pinpoint stars from edge to edge. When imaging a large target like the Andromeda Galaxy (M31), this ensures you can capture its full expanse and surrounding dust lanes without vignetting or distorted stars in the corners of your frame.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat do I need to attach my ZWO camera with a filter wheel to the UltraCat 108?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThe UltraCat 108 comes with M48, M54, and M68 adapters, making it ready for most standard ZWO camera and filter wheel combinations. You will use the appropriate adapter to connect to your filter wheel, ensuring you maintain the correct back focus for a flat field. The included Sensor Tilt Xterminator allows you to make fine adjustments for perfect sensor alignment.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eIs the 7.96 kg OTA weight of the UltraCat 108 suitable for a mount like the Sky-Watcher EQ6-R Pro?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eYes. The Sky-Watcher EQ6-R Pro typically has a payload capacity of around 20 kg (44 lbs). The UltraCat 108's total weight with rings and dovetail is 9.58 kg (21.12 lbs). Even after adding a guide scope, camera, and other accessories, the total weight will remain well within the imaging payload limit of an EQ6-R Pro or similar class mount, ensuring stable and accurate tracking.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion\"\u003e\n\u003ch3 class=\"DAV-accordion-Q\"\u003eWhat are the included M48, M54, and M68 adapters for?\u003c\/h3\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"DAV-accordion-A\"\u003e\n\u003cp\u003eThese are different-sized threaded adapters to connect various cameras and accessories. \u003cstrong\u003eM48\u003c\/strong\u003e is the most common standard for 2\" filters and full-frame camera connections. \u003cstrong\u003eM54\u003c\/strong\u003e and \u003cstrong\u003eM68\u003c\/strong\u003e are larger-diameter threads used on many large-format astronomy cameras and accessories to prevent vignetting and provide a more secure connection for heavy imaging trains.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003ctable class=\"DAV-specifications\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eLens Type\u003c\/td\u003e\n\u003ctd\u003e5-Element Advanced Petzval\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eOptical Elements\u003c\/td\u003e\n\u003ctd\u003e5 elements including 2x Super ED, 1x ED, 1x Lanthanum, and 1x X-Element glass\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eDiameter\u003c\/td\u003e\n\u003ctd\u003e108 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFocal Length\u003c\/td\u003e\n\u003ctd\u003e518 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFocal Ratio\u003c\/td\u003e\n\u003ctd\u003ef\/4.8\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eImage Circle\u003c\/td\u003e\n\u003ctd\u003e60 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFocuser\u003c\/td\u003e\n\u003ctd\u003eWIFD Rack \u0026amp; Pinion Focuser\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFocuser Compatibility\u003c\/td\u003e\n\u003ctd\u003eCompatible with ZWO EAF\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFocuser Travel\u003c\/td\u003e\n\u003ctd\u003e30 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eField Flattener\u003c\/td\u003e\n\u003ctd\u003eNot Required\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCamera Format Support\u003c\/td\u003e\n\u003ctd\u003eMedium Format, Full Frame, APS-C, M4\/3\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eT-Mount Support\u003c\/td\u003e\n\u003ctd\u003eCanon EF, RF; Nikon F, Z; Sony E; Pentax K; MFT (M4\/3); FUJI X\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eDovetail Type\u003c\/td\u003e\n\u003ctd\u003eLosmandy-style\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTube Length\u003c\/td\u003e\n\u003ctd\u003e512.9 mm - 617.9 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eOTA Weight\u003c\/td\u003e\n\u003ctd\u003e7.96 kg (17.55 lbs)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTotal Weight\u003c\/td\u003e\n\u003ctd\u003e9.58 kg (21.12 lbs)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cul class=\"DAV-grid\"\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eUltraCat 108 Main Tube\u003c\/p\u003e\n\u003cp class=\"DAV-item-subtitle\"\u003e× 1\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eBahtinov Focusing Mask Cap\u003c\/p\u003e\n\u003cp class=\"DAV-item-subtitle\"\u003e× 1\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eMounting Rings \u0026amp; Handlebar\u003c\/p\u003e\n\u003cp class=\"DAV-item-subtitle\"\u003e× 1\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eSensor Tilt Xterminator \u0026amp; Rotator\u003c\/p\u003e\n\u003cp class=\"DAV-item-subtitle\"\u003e× 1\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eM68, M54, M48 Camera Adapters\u003c\/p\u003e\n\u003cp class=\"DAV-item-subtitle\"\u003e× 1\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eVixen-style Plate\u003c\/p\u003e\n\u003cp class=\"DAV-item-subtitle\"\u003e× 1\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eSoft Carry Case\u003c\/p\u003e\n\u003cp class=\"DAV-item-subtitle\"\u003e× 1\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli class=\"DAV-grid-item\"\u003e\n\u003cdiv\u003e\n\u003cp class=\"DAV-item-title\"\u003eAllen Key Set\u003c\/p\u003e\n\u003cp class=\"DAV-item-subtitle\"\u003e× 1\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\n\u003cli\u003e\n\u003ca href=\"https:\/\/davidastro.com\/pages\/william-optics-warranty-policy\" rel=\"noopener\" target=\"_blank\"\u003eWilliam Optics 2-Year Warranty\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"William Optics","offers":[{"title":"Default Title","offer_id":50180567367965,"sku":"WO-T-C-108BR","price":3998.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0753\/5280\/1565\/files\/William-Optics-UltraCat-108-1.jpg?v=1753236705","url":"https:\/\/davidastro.com\/fr-us\/products\/william-optics-ultracat-108-f-4-8-wifd","provider":"David Astro","version":"1.0","type":"link"}