Specific to the TOA-130F and TOA-150 refractors, the 645-RD reducer is simply an optical piece of art, as only Takahashi can conceive some. On the TOA-130F, it reduces the focal length of 1000mm (F/7.7) to 760mm (F/5.8), offering a image circle of 65mm (60% not vignetted). The deep-sky wide-field astrophotographers will make this accessory as a first choice.