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Steve, if you look through an eyepiece against a moderately bright background (but definitely, NOT the SUN!) you will see the internal 'circle' (aperture) of the eyepiece - this is the 'field stop' Astro744 referred to... If the edge of the circle is sharp and uniform all the way around, chances are the eyepiece will be of reasonable quality... Regards, Andy
Last edited by Handy Andy; 01-03-2010 at 01:22 AM.
Reason: Amendment
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