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    Default Chip along top of secondary mirror. ok?



    Xt10''orion 4.7f. When I first received my scope I noticed a longitudinal "chip-out" along the top surface of the secondary mirror, that ended very slightly over the secondary bright surface. I put some sticky felt in a simi-circle around the top. Anyway orion sent me a new one. This new one had a black oval line in the middle of the secondary mirror. I had no idea how to remove the old one safely. So now if I replace it: Will it help in collimation (no crosshairs or laser,just collimation cap,chishire,autocollimator)? Should I put felt on either one, to cut down on scattered light, for the one I choose? Or just leave the old one in? I heard orion uses a slightly larger secondary. Pat

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  2. #2
    jenniferchristine's Avatar
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    Default

    No, I don't think so. If black material was needed, it would be applied by the makers -
    The oval is round when seen from the focuser hole, I think it will help in secondary alignment and collimation - is there no info in your paperwork?
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  4. #3
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    Orion just sent the secondary. I've never heard of one having an oval. Pat

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    Default

    You can use a black marks a lot and carefully blacken the edge of the secondary all the way around. This improves contrast as the side of the secondary mirror can reflect off axis light into the focuser. This same edge blackening is used on many eyepieces that come with blackened edges on the glass elements.
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  7. #5
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    Default Darkening edge of secondary.

    Joe,
    I assume you are refering to a black "Sharpie" marker. They come in industrial super ink. Pat

 

 

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