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    Default Primary mirror question; a question about internal inclusions?



    Hi all, total newbie to reflectors here. I took out my primary mirror (borosilicate) from my XT10I to apply a center spot and to my surprise I noticed that there were air bubbles in the glass (the mirror surface visually looks perfect). Now that did not bother me too much until I inspected a bit further. Peering through the edge of the glass there was an obvious distortion that spans the entire length of the mirror. The best description I can give is to compare it with what 2 part clear epoxy looks like before it is thoroughly mixed, the inner material has “stretch marks” per-say. In addition to that it also appears as if the mirror was stratified into two distinct layers unevenly before cooling off (during the manufacturing of the blank). This anomaly is reminiscent of putting oil and water into a jar and giving it a gentle swirl. The point at which the two “layers” meet, there is an obvious depression maybe 2 MM deep and about 4 CM in length.
    Hope this description makes sense, if not let me know I can try to get an ok picture of it.

    Is this normal?
    Is this anything to be concerned about?
    Patrick
    Orion XT10I, telrad, GLP, 8-24 Hyperion zoom
    The point of life is not to go gracefully into one’s grave with a pristine body; rather, it is to go sliding in sideways, in a dustball of roadrash, screaming “HOLY S#!T , WHAT A RIDE!!!”

  2. #2
    Joe Lalumia's Avatar
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    Default

    The glass is coated OK -- correct? no pits on the surface-- ?

    Then don't worry about it -- it will have no affect on your viewing.
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  3. #3
    patrock's Avatar
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    Default

    Hi Joe. Thanks
    The glass is coated OK -- correct? no pits on the surface-- ?
    Yes, that is correct, no pits, good coating. There are no mirror surface imperfections that I can detect (with my untrained eyes).

    Then don't worry about it -- it will have no affect on your viewing.
    Good to know it wont affect the optical performance; however after seeing the anomalies in the structure of the glass itself, I am somewhat concerned about its structural integrity. I guess I’m just looking for some reassurance that the internal stresses won't cause the mirror to crack at a later date (inevitably 2 weeks after the warranty expires)
    oh and TGIF, with some warm(er) weather for the weekend
    Patrick
    Orion XT10I, telrad, GLP, 8-24 Hyperion zoom
    The point of life is not to go gracefully into one’s grave with a pristine body; rather, it is to go sliding in sideways, in a dustball of roadrash, screaming “HOLY S#!T , WHAT A RIDE!!!”

 

 

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