DESC: Low Dispersion) glass optics with high transmission multi-coatings can produce this kind of exceptional edge-to-edge sharpness and color clarity. Magnus’s ED optics produces images that are free of chromatic aberrations or color fringing. Manufactured with uncompromising attention to detail, both Magnus models feature a precision-crafted Crayford-type 2-speed fine focuser and dielectric diagonal for maximum light transmission to the included Plössl eyepiece.