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Old 02-04-2012, 02:51 PM
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alocky (Andrew lockwood)
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alocky is offline
 
Join Date: Aug 2010
Location: perth australia
Posts: 1,289
Subtract your defocussed image from your 'lights' and it will go away. Those are particularly severe Newtons rings ( or interference fringes, call them what you like). Hopefully they are originating from the interface between the doublet in your Barlow and its an easy fix.
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