0.85x reducer and flattener for Skywatcher Evostar 72/420 ED APO telescopes (with M48 screw)

These accessories are needed because refracting telescopes provide a curved focal plane. The problem is similar to the distortions observed in Newtonian telescopes: stars are not pointlike close to the edges. Usually the correctors also reduce the focal length, resulting in faster optics.

The Sky-Watcher\'s new correctors are designed especially for their ED Apo telescopes: 80mm, 100mm and 120mm EDs, but can be used with good results in similar telescopes. They provide 0.85x reduction, so the focal lengths will be somewhat shorted (for example, the 80/600 ED becomes a 80/510, meaning that the system changes from f/7.5 to f/6.37). Provide good correction at the edges, so the correctors can be used even for 35mm format (full frame). The correction can be mounted using the standard thread and provide a larger than 2\" field. At the corrector\'s back an M48 thread is provided which is also somewhat larger than the traditional T2.