William Optics Focal Reducer & Field Flattener

This unit is specifically designed for the Gran Turismo 81, Gran Turismo 71, Zenithstar 81, and Fluorostar 91 models. It is optimized to work seamlessly with the optical characteristics of these specific refractors.

Yes, it is designed to provide sharp, flat images across 97% of a full-frame sensor. You will get excellent edge-to-edge performance for most standard astrophotography setups.

The adjustable back focus allows you to fine-tune the distance between the reducer and your camera sensor. This is crucial for achieving perfect star shapes across the entire frame, especially when using different camera bodies or filter wheels.

Yes, it features an integrated 2-inch filter cell. This allows you to easily thread your light pollution or narrowband filters directly into the imaging train without needing extra adapters.

The 0.8x reduction widens your field of view and effectively increases the speed of your telescope. This allows you to capture more of the sky in a single frame and significantly reduces the exposure time needed for deep-sky objects.

This reducer uses premium Ohara glass, which is highly regarded for its superior clarity and low dispersion. Combined with fully multi-coated surfaces, it ensures maximum light transmission and minimal internal reflections.