Telescope-Refracting Telescopes-William Optics Gran Turismo 81 APO Refractor w Internal Focus Design and 32mm UniGuide – Space Gray

Introducing the William Optics Internal Focus Design (WIFD)
This new focuser design includes the patented William Optics center focuser with precise internal sliding of fixed optics to prevent image shift. The integrated position viewing window on the focuser provides instant verification of the graduated numerical display. The smooth rack-and-pinion design is incorporated into the focuser to provide super fine adjustability for critical focus. The internal movement of the optical elements is protected from the elements and cannot come out of alignment. The redistribution of weight allows for better balance during imaging sessions.

Outstanding Optics
The Gran Turismo 81 features excellent optics to get the most out of your images. The optical assembly of this refractor is in a triplet configuration, made of FPL-53 apochromatic glass to reduce chromatic aberration and provide excellent contrast, color correction, and sharpness. As mentioned in more detail above, the unique internal focuser design slides otherwise fixed optics to prevent image shift and virtually eliminate vignetting.

Included Reducer/Flattener
The included William Optics 2″ Field Flattener/Reducer has been designed to optimize the flat-field imaging performance of the GT81. The APO triplet optics of the Flat6AIII are made with Ohara glass and fully multi-coated to provide good illumination and a beautifully flat field across 97% of full frame sensors. The reducing factor is 0.8X. Designed with M63 threads on the telescope side, this flattener/reducer threads directly into the telescope. The Flat6AIII has 2″ threads on the opposite side to accept a 48 mm (Wide) T-ring for your DSLR. There is even a slot behind the 2″ threads to accept an M48 filter.

Included Slide-Base 32 mm UniGuide Finder Scope
The included 32 mm UniGuide guide scope has a focal length of 120 mm and a focal ratio of f/3.75 and mounts into the handle of the Gran Turismo 81. The back of the UniGuide comes with an M42 thread for attaching 1.25″ cylindrical-type guide cameras such as those by QHY, SBIG, and ZWO. Tightening knobs will ensure a stable fit for the attached guiding equipment.

Additional Accessories
The William Optics Gran Turismo 81 WIFD comes with several accessories to improve performance and convenience. In addition to the included flattener/reducer, UniGuide finder scope, and internal focusing mechanism, the GT 81 includes a Rotolock field rotator which allows for precise and convenient orientation of a connected camera. The Bahtinov mask aids in focusing. The optical tube rings and dovetail allow for easy mounting. The included handle doubles as a shoe for attaching small accessories, such as a finder scope. Lastly, a soft carrying case is included to make transportation a breeze!