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Old 02-03-2008, 01:49 PM
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tbentley
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Join Date: Oct 2006
Location: South Hedland, WA
Posts: 64
Quote:
Originally Posted by Kokatha man View Post
"Many eyepieces have an eye relief (distance of exit pupil from eye lens) that is directly related to its focal length. For example, the eye relief of a Plössl is 0.73 × its focal length. Thus, with these eyepieces, for a given magnification there will be greater eye relief with a barlow than without."

That staement confused me when put in the context of the ray trace of the barlow. The diagram shows an increase in the focal length of the objective and doesn't affect the focal length of the eyepiece so therefore(?) the eye relief shouldn't be affected if the above is true.
Any comments on my second attempt at an eye relief ray trace diagram Scoper? If it's right then it seems to explain the phenomenon but I can't find confirmation anywhere. Is there an optician in the house?
Trav
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