The revolutionary William Optics Flattener IV was designed and produced by William Optics. Although a perfect match to the 98FLT it wil suit any high-quality refractor with a focal length of 500-1000mm. Unique twist-adjustable back-focus. 2" fitting for universal use.

Super-Transmission-Coated with 2-element unit was designed and produced by William Optics, the inner flattener lenses can be set at the optimum 66mm-86mm back focus by simple hand twist (Distance from flattener lens to film or CCD plane).

This accessory is a must-have for refractor astrophotography.

Lens

• Designed to cover full size DSLR cameras with clear lens aperture of 54 mm
• STM coated with excellent doublet air spaced design.
• Produced entirely with the best Ohara optical glasses.

Amazing

• Reducing factor 0.75-0.8X.
• It will flatten the field amazingly well and finally make you see those stars round!
• This unique flattener works with WO's or other 500-1000mm focal length refractors.

• Takes FLT-98 to 490mm f/5.0 and the FLT-110 to 615mm f/5.6.

Superb Finish

• Superb William Optics anodized finish.
• All internal surfaces threaded and blackened for no reflections.

Easy to Use

• Rotating T-ring thread for any 35mm camera. The T-ring adapter is provided with a lock screw and extra lock retaining screws.
• Will accept any standard T-ring for your camera.
• Inserts directly into 2" focuser.
• Suitable for M90, FLT98, FLT110, FLT132 and many others.