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reflections from focuser tube

reflections from focuser tube

View through the EON 115mm OTA and Williams Optic Flattener IV. The diffuse reflections is from the focuser draw tube. It is already blackened and roughened, but still shows a fair amount of reflections. I have ordered some BLACK 2.0 super blackening paint to recoat the draw tube. This is a source of at least some reflections in the optical train but it is not clear how much this is causing the flats issues. I have previously used this OTA many times with DSLRs and have seen no such issues with flat frame artifacts, but the reflectivity of the draw tube could and should be improved.

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