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Premium Triplet Option—The William Optics FLT91!
With 91 mm of aperture the William Optics Fluorostar 91 sits in the”mid-sized” space of the company’s fantastic refractor offerings, but itsperformance is anything but middling! With premium optical elements used inits triplet design, this scope provides stunning apochromatic images for boththe visual observer and astrophotographer alike. Experience powerful, fullyfeatured, refractor performance, with the William Optics Fluorostar 91 FPL53Triplet APO Refractor with 3.3″ Rack & Pinion Focuser!
At the heart of the William Optics Fluorostar 91 (FLT91) refractor is atriplet optical design. With FPL-53 glass used, this three lens design is ableto provide impressively sharp and apochromatic images for clear,color-fringing-free, views. Building on this strong foundation, William Opticshas included an excellent set of supporting hardware: premium gray anodizedaluminum rings, a V-style dovetail with an extended with top plate,dual-function handle and Synta accessory mount top rail, large 3.3″ rack andpinion focuser, 360° rotator, and a RotoLock 2″ visual back! This all addsup to a powerful and fully-featured refractor capable of providing stunningviews and images of larger deep sky objects with its 540 mm focal lengthoptics!
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A Premium Mid-Size Triplet Refractor
Featuring premium triplet optics, a quick and secure 2″ visual back, rock solid focuser, dedicated astrophotography accessories, and all the essential hardware you need, the William Optics Fluorostar 91 FPL53 Triplet APO Refractor makes a strong case for the optical core of your next astronomy rig!
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Superb FPL-53 Triplet Optics
The FLT91 refractor uses a triplet optical design, which provides chromatic-aberration correction. Ensuring your views will be apochromatic and tack-sharp, William Optics has used FPL-53 glass in this design, which provides this enhanced performance through its super ED characteristics. With a 91 mm front aperture and f/5.9 focal ratio, this scope offers bright views and a 540 mm focal length window into the universe.
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Fast 2″ Accessory Changes
Where more conventional visual backs feature thumbscrews, the Fluorostar 91 features William Optics’ RotoLock for quicker 2″ eyepiece and equipment swaps. With just a short twist the RotoLock can be loosened to remove your current eyepiece or accessory and then re-locked with a quick twist back. This system is more than just convenient, featuring a solid lock up to ensure your equipment changes are speedy and secure!
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Robust Rack and Pinion Focuser
For comfortably carrying today’s sometimes quite stout and demanding equipment trains, the FLT91 comes equipped with a large 3.3″ rack and pinion focuser! This features a massive M92 connection to provide an obstructed view for either the included 2″ RotoLock or the dedicated Ultra Flat 0.79x Reducer (sold separately) and a dual-speed focus knob for precisely finding your perfect image or view. For those looking to add a more automated focusing system, this focuser can accept bracket style electronic focusers like the ZWO Standard Electronic Automatic Focuser right out-of-the-box. Finally, for simple framing adjustments and gear rotation, this has an integrated 360° rotator; simply loosen the thumbscrew, adjust your gear, then snug down the thumbscrew to lock your gear in place.
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Astro Photo Adaptation: Ultra Flat 91 (Sold Separately)
For those looking to maximize the astrophotography performance of the Fluorostar 91, the William Optics Ultra Flat 0.79x Reducer is for you! This corrective element is designed to integrate seamlessly with the FLT91, replacing the 2″ RotoLock for a secure a sleek connection. With a 0.79x reduction factor this transforms your scope into a wider FOV, brighter, and full-frame corrected astrophotographypowerhouse; providing a f/4.7, 424 mm focal length view into the night sky across a 43.2 mm image circle.
This reducer and telescope are available together in a bundle as well!
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Included Accessories
The William Optics Fluorostar 91 FPL53 Triplet APO Refractor with 3.3″ Rack & Pinion Focuser comes with a number of essential and handy accessories that make it a solid foundation for a wide variety of imaging and observing builds. A pair of anodized rings hold the FLT91 securely to the V-style connection, extended width, dovetail bar and the dual-function handle/findershoe base accessory top rail. These feature large knobs to make removing the scope or adjusting it a breeze. For the astrophotographer, this scope also sports William Optics’ excellent Bahtinov mask dust cap—featuring a focusing screen behind a removable front cap that makes nailing focus simple. This scope also features an analog thermometer coarse focus knob, for a bit of added functionality and scientific flair! Finally to make storage and transport simple and secure, William Optics has included a foam padded soft carry case.
Astronomy Hub: Your one-stop-shop for Astrophotography Knowledge!
Our Gear Experts have compiled a wealth of information to help expand your astrophotography knowledge! Below you’ll find links to articles, videos and “how-to” guides. Just one more reason that our Astronomy Hub is a one-stop-shop for all your astronomy and astrophotography needs!
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