Ask Astro: What causes the pattern of diffraction spikes in astronomical images?

The spikes around bright stars in deep images are caused by the way light interacts with the shape of a telescope’s mirrors and the struts holding them.

How to Make [Legit] Diffraction Spikes on Stars with a Refractor

Astrophotography

Diffraction spike - Wikipedia

Diffraction spikes rotation on Alt-Az telescope

Diffraction spike - Wikipedia

x-bit-astro-imaging: Diffraction spikes attractive and sometimes

Diffraction spike - Wikipedia

Side by side comparison between the James Webb SMACS 0723 (left

Question (image from PEARLS field): Why are the diffraction spikes