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How's the primary mirror looking? A sqizz down the tube will show a lot. Also, have a look at the rear end of the scope so you can see the backside of the primary. Then have a bright light shine down the tube onto the primary - can you see any pin-pricks of light shining through the primary. This will tell you a lot about the condition of the primary - no pin-pricks of light is ideal. Few pin-pricks, yeah ok but not great. Many pin-pricks (or worse, big holes in coating) scope still usable (just and not great by a long shot) and not worth very much.
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