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@REPLYADDR Martin Brown
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@REPLYTO 2:5075/128 Martin Brown
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On 16/09/2023 12:59, Quadibloc wrote:
> On Saturday, September 16, 2023 at 4:34:03 AM UTC-6, RichA wrote:
>>
https://phys.org/news/2023-09-large-space-telescopes.html
>
> Up until now, space telescopes didn`t use adaptive optics.
>
> The article claims that if a space telescope were launched with a 6.5
> metre mirror made from a single borosilicate glass blank, though, it
> would be needed. Since there`s no atmosphere to worry about, I suppose
> the culprit is thermal expansion of the mirror itself.
More likely differential thermal expansion of the support structure as
it goes in and out of the Earth` shadow. Pre HST launch much of the
knowledge about those thermal effects were highly classified.
--
Martin Brown
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