This William Optics 2" Field Flattener & Reducer has been designed to optimize the flat-field imaging performance of William Optics GT71, GT81, Z81 & Z103 refractors. The APO triplet optics of the Flat6AIII are made with Ohara glass and fully multi-coated to provide good illumination and a beautifully flat field across 97% of full frame sensors. The reducing factor is 0.8X.
Designed with M63 threads on the telescope side, the FLAT6AIII will thread directly into the telescope. Just remove the three screws on the focuser adapter, take off the adapter, and thread the focal reducer/field flattener on in it's stead. The Flat6AIII has 2" threads on the opposite side to accept a 48mm (Wide) T ring for your DSLR. There is even a slot behind the 2" threads to accept an M48 filter.
Finally, if you take a look at the pictures to your left, you will notice that the FLAT6AIII is adjustable to help you achieve the proper back focus. Adjustment distances & back focus, as well as the image circle measurement for each of the telescopes are listed below.
