SHARPSTAR 0.95X 2" Coma reducer corrector This new product can be used alongside the Newtonian reflector on the market for astrophotography, which has excellent performance and is easy to use. 2" corrector is designed for APS - C (28mm in diameter) imaging circle correction, suitable for most of sold F3-F6, 150mm~600mm aperture of Newtonian reflector and the prime focus system can change the focal ratio of F4 to F3.8, F5 to F4.75, F6 to F5.7, reducing the required exposure time and improving the peripheral star image quality, the center star can be controlled within 10 microns in diameter. SPECIFICATIONS: Model:150mm-600mm, paraboloid reflector Focal ratio:F3-F6 Magnification: 0.95x Image Circle: 44mm,the optimal Image of 28 mm. Number of lenses: Triplet Outer diameter mirror:2" Back focus: 56mm Overall Length: 79.7mm Optical Coatings: Fully multi-coated Weight: 0.22kg