Virtually Eliminates Residual Chromatic Aberration Pride and Perfection in Optical Manufacturing Metallic High-Transmission Lens Coatings: Each air-to-glass lens surface has exotic anti-reflection metallic coatings applied to ensure optimum light through-put. The proprietary Skywatcher Metallic High-Transmission Coatings (MHC) are the finest photon anti-rejection coatings in their class Light-Baffled Optical Systems: The objective lens cell is light-baffled to reject stray, unfocused light. The draw tube is likewise baffled to insure optimum contrast. The tube interior is flat blackened to help prevent unfocused internal light reflections from reaching the focal plane Precision 2 Crayford-style Focuser is Standard: Optical focus is achieved by means of a mechanically ultra-smooth, backlash-free, precision 2 Crayford-style rack & pinion focuser-assembly with 1.25 adaptor. Focuser offers 2 speeds for fine and ultra-fine focusing adjustments