Eye relief is the distance, expressed in millimeters, from the ocular (eyepiece) lens to the point where the eye is positioned to view the entire image.
Large telescope lens or telescope mirror(called an entry filter ), not placed over the small eyepiece lens you would look through(called an exit filter.
Hans lippershey s invention had inspired galileo to construct a scope consisting of a convex objective and a concave eyepiece lens in a scope that is today referred to as a galilean.
Using an eyepiece rather like using a microscope.for any given size of primary optic, lens or by using a large, shallow curved eyepiece lens, (long focus) a wide angle, low magnification view.
Measures distances from 50 to 920 yards with + 2 yards deviation when used correctly no high-energy transmitter 5x magnification objective lens 20mm lens diameter 12mm eyepiece lens diameter 7.
.1 aspherical eyepiece lens action ex $ 190 7x35 s p fmc yes, 9.3 15 15 tu 25.0 waterproof fogproof action $ 110 8x40 s p mc, - 8.2 15 12 fd 26.6 aspherical eyepiece lens action ex $ 199 8x40 s p.