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Modifying a refractor

Discussion in 'Telescopes and Mounts' started by Gabby76, Aug 16, 2023.

Modifying a refractor

Started by Gabby76 on Aug 16, 2023 at 11:27 AM

6 Replies 658 Views 2 Likes

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  1. Gabby76

    Gabby76 Well-Known Member

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    Gabby76, Aug 16, 2023
    #1
    In April I ordered a Bresser Messier AR-127/ 1200 to use as a platform for making a dedicated binoviwer telescope.
    It finally arrived on 14 August and after checking collimation and a indoor star test I took it outside for a quick daytime assessment.
    Eyepieces used were a Antares Elite 10 mm for just over 1 mm exit pupil and a 18 mm Fujiyama HD which gives just under a 2 mm exit pupil.
    Targets were high contrast areas of electrical tower, row of trees and housing approximately 500-750 meters away.

    The view was crisp with SA well controlled and surprisingly less colour fringing than I was expecting with a 127 mm Baker doublet. So far I am quite pleased with the views. :)
    (For giggles I tried a Nikon 5 mm orthoscopic at 0.53 exit pupil and the views were still very good.)

    Since I want this as a dedicated binoviewer telescope, the winter project will be to shorten the tube so no OCA is required with a 2" mirror diagonal+BV.
    Shortening the tube will require the removal of the rear tube baffle as well so I will calculate new positions and install 5 new ones instead of the standard 3 from factory.

    https://www.bresser.de/en/Astronomy...essier-AR-127L-1200-Hexafoc-Optical-Tube.html
     
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  2. sojourneyer

    sojourneyer Well-Known Member

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    sojourneyer, Aug 16, 2023
    #2
    Here is something I came across many months ago. Quite interesting bino approach. If you would like to see more I can direct you to the webpage..


    325849318_1192563364716573_483351241283362940_n.jpg
     
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  3. sojourneyer

    sojourneyer Well-Known Member

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    sojourneyer, Aug 16, 2023
    #3
  4. Gabby76

    Gabby76 Well-Known Member

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    Gabby76, Aug 16, 2023
    #4
    Interesting that they are using 2 Maksutov for the bino-scope.
    Those rotatable diagonals are very expensive though!

    Not exactly what I will be doing though, I will just be using my Stellarvue and Baader Maxbright binoviewers with the telescope and cutting/ shortening the tube just so there is no OCA required to come to focus.
     
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  5. Ed D

    Ed D Well-Known Member

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    Ed D, Aug 21, 2023
    #5
    That's a very interesting project. I'm looking forward to following your progress.
     
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  6. sojourneyer

    sojourneyer Well-Known Member

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    sojourneyer, Aug 22, 2023
    #6
    No, that is a scope from someone on Japan. I just thought I would share it with the members.
     
  7. Gabby76

    Gabby76 Well-Known Member

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    Gabby76, Sep 15, 2023
    #7
    When I do this I will be using a mirror diagonal instead of shortening the path by using a prism diagonal.
    A prism diagonal used with BVs can cause cross polarization between the two which will dim one eyepiece.

    If you use a Herschel wedge for solar viewing, or just observe with a prism, here is a handy tip for you if you have a variable polarizer filter.
    Take 1 part of the filter and place it on the bottom of the eyepiece. If you want to dim/ brighten the view just rotate the eyepiece as the wedge/ prism diagonal and eyepiece will now act as a variable polarizer.
     
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