William Optics Fluorostar 91 (aka FLT-91) SG / space grey OTA (SKU: T-FLT-91)

The William Optics Fluorostar 91 is a remarkable optical instrument meticulously designed to meet the demands of astrophotography, ensuring unparalleled image quality that surpasses other telescopes of its kind. With a focus on selecting top-notch materials and maintaining exemplary precision in craftsmanship, the designers and engineers at William Optics have created a refractor that guarantees superb optical performance, as demonstrated by its impressive Strehl coefficient of over 0.95.

At the core of this refractor lies an apochromatic triplet optical system, featuring lenses crafted from premium glass, including the high-performance FPL-53 glass from the renowned Japanese company Ohara. This glass possesses an exceptionally high Abbe number of 94.49, indicating extremely low dispersion characteristics. To further enhance image quality, all lenses are equipped with a multi-layer anti-reflective coating, ensuring sharpness and high contrast.

Thanks to its generous illumination disc diameter, the Fluorostar 91 is ideally suited for use with cameras and SLR cameras equipped with both full-frame and APS-C sensors, making it a versatile tool for astrophotographers.

Key Features of the William Optics Fluorostar 91 Refractor:

• Apochromatic Triplet: Crafted from FPL-53 glass and coated with a multi-layer anti-reflective coating, the triplet design guarantees exceptional color correction and reduced chromatic aberration.
• CNC-Machined Mountings: The fasteners are precision-engineered using CNC technology, ensuring a secure and stable setup.
• William Optics Patented Bahtinov Mask Design: The Bahtinov mask, equipped with a convenient handle, aids in achieving precise focus for astrophotography.
• Full Illumination Circle: The refractor boasts a large illumination circle, providing complete coverage of a full-frame sensor.

Technical Specifications:

• Optical System: ED-APO Apochromatic Triplet
• Objective Diameter: 91 mm
• Focal Length: 540 mm
• Focal Ratio: f/5.9
• Lens Material: Premium optical glass, including FPL-53 (Ohara, Japan)
• Anti-Reflective Coating: Full Multi-Layer Coating (FMC)
• Strehl's Coefficient: > 0.95
• Full Illumination Circle Diameter: Suitable for full-frame sensors
• Compatible Sensor Sizes: APS-C, Full Frame
• Compatible Photographic Systems (via interchangeable T-rings): Canon EF, Nikon F, Sony E, Pentax, Micro 4/3, Fuji FX
• Focuser: 3.3"
• Eyepiece Type: Rack & Pinion, Dual Speed
• Recommended Flatteners: WO Flat 6A III x0.8, WO FLAT 68 III x1.0
• Finder Foot: Vixen
• Folded Tube Length: 441 mm
• Extended Tube Length: 510 mm
• Tube Weight: 4.2 kg (Total Weight: 5.5 kg)
• Tube Finish: White-Grey (Space Gray)

Included Accessories:

• William Optics Fluorostar 91 Refractor
• Vixen Mounting Plate
• Bahtinov Mask with Mount
• Mounting Bracket
• Transport Bag
• Spacer Tube

Warranty:

The William Optics Fluorostar 91 comes with a 24-month warranty, ensuring peace of mind for your investment in this exceptional refractor.