William Optics FLAT6AIII 0.8x Field Flattener for FLT 91
This William Optics field flattener is designed specifically to work with the FLT 91 APO refractor. The APO optics of the Flat6AIII flattener are made with Ohara glass and are fully multi-coated to provide good illumination and a beautifully flat field across 97% of full frame sensors. The reducing factor of this field flattener is 0.8x. You will notice that the FLAT6AIII is adjustable to help you achieve the proper back focus. The adjustable distance for DSLR and Mirrorless cameras is 5.4 mm.
The FLAT6AIII will thread directly into the FLT 91 telescope. All you need to do is remove the three screws on the focuser adapter, take off the adapter, and thread the focal reducer/field flattener on.
The body of the flattener is made of high-quality material and anodized black with grey accents.
