Open tube SCTs

Hi all,

I was sitting around a few weeks ago with a buddy of mine and we got to
talking about different scope designs and I got to wondering if there
has ever been a truss rube SCT or Mak designes and or built. If so what
were the results?

I imagine it would cool down very fast, though dust on the optics could
be an issue.

If it hasn't been done why not? Is it a collimation issue? What about
cutting slots in the OTA to help speed cooldown.

Thanks

Craig

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