CDK17 – Optics shipped!

My Optics are ready and are shipping! I should have them within 4 weeks. I received the final optical specs (namely spacing between the different elements) which will allow me to finalize the structure. I found that the front of the scope was a little too light so in order to avoid having to add counterweight to the front of the OTA, I had re-machined the front ring, made some changes to the CF tube ends/fittings and used thicker CF tubes. I was waiting on these final specs before I cut the tubes to length.

I am not an expert in Optical engineering, testing. I am not afraid to admit the test results below don’t talk to me too much. I will judge the quality when I start taking pictures and hopefully I will be happy!

First, here’s the Ronchi test:


Next is the Foucault test:


And here’s the data from the Foucault test:


I can’t wait for the first light – I’ve got quite a bit of work ahead of me, I need to get busy now!

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4 Responses to CDK17 – Optics shipped!

  1. 민태훈 says:

    Oh, congraturation!. I’m considering to buy a Hubbleoptics CDK17, too. But I’m not good at CAD at all(I’m meshed up how to do). I hope you’ll succeed in the first light…
    = Richard=

  2. rbrooks says:

    Thanks for these detailed write-ups both here and at CloudyNights.

    Question: Are you using any sort of special edge support on your mirror, or does the central bore hold things in place well enough?

    Curious about this as I’m reaching cell designs for mirrors on GEMs, and so much of the existing information is for dobs, which are easier to support.

    Thanks again!

    • zytrahus says:

      Hi Ryan,
      Yes, in addition to the 18-point mirror cell I have lateral support (6-point) for the mirror. The parts for the lateral supports were not made when I first assembled the structure. I will make a new post about the scope when I install the optics and put everything together! I made some small design changes to the structure too (larger CF tubes and a heavier secondary ring because the scope was a little back heavy, so I figured it would make more sense to stiffen everything a little bit instead of just adding dead weight)


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