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IMG 8534 1024


IMG 8534 1024


    I have completed a rebuild of the gso 150mm f4 scope including mirror mask, rebuild of the mirror cell with better springs and bolts, flocking, enhancement to the spider, a top mounting / bracing bar etc. I have been using it with the sky watcher anapalantic coma corrector and the results have been excellent. I decided to go for speed and bought the nexus .75 coma corrector and can't get focus. I am going to need to move the mirror cell up the tube to achieve focus but I am unsure how much I will need to cut. My guess is somewhere between 25mm and 40mm?  Does any one have a more accurate number?  Thanks Ross

      • Hindsight2020 likes this
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    Hindsight2020
    Feb 15 2024 04:38 PM

    I have completed a rebuild of the gso 150mm f4 scope including mirror mask, rebuild of the mirror cell with better springs and bolts, flocking, enhancement to the spider, a top mounting / bracing bar etc. I have been using it with the sky watcher anapalantic coma corrector and the results have been excellent. I decided to go for speed and bought the nexus .75 coma corrector and can't get focus. I am going to need to move the mirror cell up the tube to achieve focus but I am unsure how much I will need to cut. My guess is somewhere between 25mm and 40mm?  Does any one have a more accurate number?  Thanks Ross

    Here is how I made it work without cutting the tube - Basically by simply changing the bolt lengths for the mirror cell, and using or not using a short 20mm focuser extension. No tube mods required

    I am able to run the Paracorr and the Starizona Nexus reducer on the same scope with the following tricks:

    1. For the Paracorr: I run a 20mm focuser barrel extender from TS-Optics for my TS-Optics UNC focuser and I add more shims to the primary mirror cell adjustment bolts to help move the primary back nearly as far as it can go in the cell.

    2. For the Nexus: I remove the 20mm focuser barrel extender, I run longer bolts for my primary mirror adjuster that extend the primary mirror forward about 5-10mm, and I remove the focuser extension barrel.

    I run the very tall (35mm!) Baader clicklock for both devices as it has the best repeatable centering.

     

    The difference in distance needed between the Paracorr and Nexus is about 25-30mm. But it would be less of a difference between the Nexus and Stock (no coma corrrector). 




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