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Message: <blockquote data-quote="Omid" data-source="post: 3441809" data-attributes="member: 16724">@Binastro: Yes, if you look through a Galilean viewfinder in reverse then you will observe that it is very easy to see the image even if you look from the sides or from a distance for the view finder. This is because the exist pupil of such a view finder is naturally large (=diameter of the objective lens). You will notice the same thing if you look through the objective side of a pair of binoculars (say 8X42) too! It is very easy to view the image and there is no ``eye relief''. The above phenomena have been well known. A Galilean viewfinder and a revered binocular are both "minifying" instruments. It is also possible to get a very large exit pupil if you make the objective lens very large or you lower the magnification (note: exit pupil diameter = objective diameter / magnification). So, if you make a 6X120 binoculars, they will have huge exit pupils (20mm wide) and it would be very easy to look through them. These phenomena are not what we are talking about here. What we are discussing is a normal (not reversed) Keplerian telescope or binoculars with normal magnification (say 10x) and normal objective diameter (say 50mm) but having an exit pupil far larger than 5mm and further having no critical eye relief. That's the result of my invention. Regarding the video clip, I am not sure what the problem is/was. Maybe we change the https to http in the link it will work better:<a href="http://vimeo.com/178946233" target="_blank">http://vimeo.com/178946233</a>@Ronh: Here is my core patent on this innovation (more are pending): <a href="https://www.google.com/patents/US8749884" target="_blank">https://www.google.com/patents/US8749884</a></blockquote>

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