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08-04-2022, 02:46 PM - 10 Likes   #1
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More on Webb telescope diffraction pattern

A few weeks ago, a post about the first Webb pictures included comments and discussions about the diffraction spikes so prominent around bright stars in the Webb images: Nasa Webb image -

For those who might be interested, here's a somewhat more in-depth of what causes the strongest of those spikes: Why stars look spiky in images from the James Webb Space Telescope - The Verge

For the most complete explanation, makes sure you go all the way through the article.

The spikes are, indeed, mostly due to the overall hexagonal shape of the primary mirror and the struts supporting the secondary mirror. I found it most interesting that the designers oriented the struts so that some of their effects would overlap with the effects from the primary mirror. Otherwise, there would be EVEN MORE spikes around the bright stars!

08-06-2022, 06:13 AM   #2
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Interesting read! I also found it interesting that the design took into account the effects of struts and hexagonal mirror elements. I wonder if the honeycomb mirror design will ever find its way into amateur telescope design? I have made several Dobs and the thought of three support stunts never occurred to me. All of mine were sonotube-based with traditional support vanes.

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