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Re: [Telescopes] Collimating a Newtonian Refractor Telescope

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  • Geoff Gaherty
    ... 1. Make sure the focuser is square to the tube by removing the secondary, marking the spot directly opposite the focuser, and sighting through the focuser.
    Message 1 of 3 , Jan 4, 2013
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      On 04/01/13 6:07 PM, keithhfinelli wrote:
      > Im having a slight issue with getting the Secondary mirror lined up.
      > I have all steps correct (I think). The main issue is when looking
      > through the viewer with a collimating cap in place. The mirrors are
      > slightly off in that I cannot see all 3 points that are around the
      > circumference of the mirrors. When I adjust it with the screwdriver
      > I can get all 3 in the viewer but when I adjust the cap viewer to be
      > centered, it moves it to where only 2 of the points are in the
      > viewer. This is the only issue Im having. Is this going to cause a
      > major problem? Will it just take finesse on my part to get it right?
      > Should I take it somehwere? Or is this a non issue to worry about.
      >
      > Any help would be greatly appreciated.
      >
      > Its not far off center just enough to not see all 3 points. I hope
      > you know to what Im referring when I mention these parts.

      1. Make sure the focuser is square to the tube by removing the
      secondary, marking the spot directly opposite the focuser, and sighting
      through the focuser. A crosshair collimator like Orion's helps.

      2. Make sure the secondary is directly under the focuser by adjusting
      its position.

      3. Make sure the primary is centred in the secondary by adjusting the
      secondary (in and out, then tilt). This is where you should see all
      three mirror clips.

      4. Adjust the primary so that the secondary is centred on it. Again a
      crosshair in the collimator helps, as does a centre spot on the primary.

      5. Go back to step 2, and repeat the sequence until all is concentric.

      There are good instructions here:

      http://www.backyardastronomy.com/Backyard_Astronomy/Chapter_15__Polar_Alignment,_Collimation,_Cleaning_and_Testing_of_Telescopes_files/Appendix%20B-Collimation.pdf

      Geoff

      --
      Geoff Gaherty
      Foxmead Observatory
      Coldwater, Ontario, Canada
      http://www.gaherty.ca
      http://starrynightskyevents.blogspot.com/
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