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Old 15-09-2016, 09:48 AM
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RickS (Rick)
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Quote:
Originally Posted by glend View Post
That was pretty much what Wolfi at Tekeskop-Express said, that carbon fibre should not be used on closed tube scopes,, which explains why all their carbon tube offerings are newts or RCs or other open tubes. I noticed looking through their refractors that everything is alumimium tube.
The reason that Roland @ Astro-Physics gives for using aluminium tubes for his refractors is that the dimensional changes in an aluminium tube due to temperature change tend to compensate for changes in the focal length of the objective, giving overall better thermal stability.

This isn't going to be a significant factor for closed tube catadioptric designs where I presume the main disadvantage of a CF tube would be a longer cool down time.

Cheers,
Rick.
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