Two-element design incorporating one ED element. Reduces the standard focal length of the Evolux-82ED by a factor of 0.9x and provides top quality field-edge correction. The flattener / reducer illuminates a full frame format and provides pinpoint star imaging over a 36mm image circle. Provides focal length of 360mm & f/5.8. Field of View 4.34°. Back focus 55mm. Fully multi-coated. Supplied with adaptor/field-rotator. Filter thread inside adaptor to mount 2" filters. M56x1 female / M48 male threads. Can be used in conjunction with Sky-watcher’s M48 Canon or Nikon T-ring adaptors (product codes 20237 & 20238).