Quote:
Originally Posted by skysurfer
Can the manufacturers not 'downscale' the large and long FL eyepieces like the Ethos 21 'downscale' (resizing all elements) retaining its design ?
Presumably I think too simply.
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I noticed no one actually answered your question... so I shall try, using my *very* limited knowledge in eyepiece design (i.e. none, but I'm an engineer, so I B.S. very well
... and love BS'ing...
)
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Consider the FOV claimed by the manufacturer. If one considers the overall design from a "reverse engineering" point of view, then the only way to get that type of
apparent FOV is to have a medium that allows an exit large enough to encompass it (i.e. the last ocular must be the size of the pupil, diverged away at the distance of the eye relief such that the angle of the FOV equals the diameter of the last lens, holy smoke did that make sense???)
So, this defines the minimum diameter...
From there, we back calculate all of the elements to the point where we get to the entry point for a 1-1/4" or 2" eyepiece barrel and presto!, we have the overall design...
figure in the weight of glass, steel/aluminum/carbon fibre/any material required to hold the elements together and you get the eyepiece... who's weight is the summ of its parts.
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OIC!