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C14 Primary Retaing Ring Mod

Discussion in 'Telescopes and Mounts' started by Scopejunkie, Sep 21, 2018.

C14 Primary Retaing Ring Mod

Started by Scopejunkie on Sep 21, 2018 at 1:55 PM

2 Replies 390 Views 1 Likes

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  1. Scopejunkie

    Scopejunkie Well-Known Member

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    All,

    Though this is not telescope making, it is a telescope mod. I'm hoping that this might help someone that has a large SCT the won't maintain "star level" collimation. I noticed on my "OLD" C-14 that the collimation would shift when viewing different parts of the sky. I'm not talking about gross mirror tilt. I'm speaking of the type of primary tilt that shifts the diffraction ring on an in focus star at high power (300x or greater).

    My scope has really great optics so this minor tilt became quite annoying to this multiple star observer. When I pulled the primary the retaining ring was still in contact with the primary but was not "tight." I installed 3 nylon tipped set screws (10-24) into the retaining ring. I reinstalled the ring tight then screwed down the set screws firm but not overly tight. The problem appears to be fixed. After star level collimation (in focus) the first diffraction ring has remained centered on the airy disk over the past week of observations. We shall see how well this works long term.

    I made this mod because I don't want to have to take this scope apart ever again for as long as I own it.

    Keith (Scopejunkie)
     

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    Dave In Vermont likes this.
  2. Dave In Vermont

    Dave In Vermont Well-Known Member

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    Wow! You're brave to have done this very well planned-out fix! My congratulations as well as amazement!

    Those Nylon® - Screws/Bolts are excellent parts to have on-hand. Every well-equipped astronomer should have-get these and add them to the kit.

    All The Best.

    Dave

    <edit> wrong placement
     
    Last edited: Sep 21, 2018
  3. Scopejunkie

    Scopejunkie Well-Known Member

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    Well... after almost 4 months of consistent observing and cold winter nights, no change in collimation at all. :)The testing continues...
     

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