28 INCH Quartz Glass Reflector telescope Parabolic primary mirror For Sale
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28 INCH Quartz Glass Reflector telescope Parabolic primary mirror:
Paraboloidal primary mirror diameter of Outer circle716 mm,Effective diameter 713mm(≈28 INCH),the focal length of 2930 mm, I personally ground, polish, hand figure, no vacuum aluminum plated with . 266 times the perfect imaging（100-266X713）. Quartz Glass , edge thickness 25 mm, weight 17 kg(Quartz Glass 2.22g/cm3,Is the lightest glass). Coefficient of expansion approximately equal0,Quartz Glass,Melting point ≈boiling point=Cloud and mist,Surface bubble wear area<1%the measure Of area, <0.004 Magnitude.I will cover the shipping .Packing EPE model with carton,Ensure that no danger of anything going wrong.Delivery only primary mirror.
Ronchi grating 4 lines per millimeter.