Warning to OP: if you remove the cartridge there might be a pin that gets removed. I always tie a string/thread to the pin while it is still in place and attach the other end of the string to the faucet/spigot so that if I accidentally drop the pin (since it is small), it doesn’t drop into the space behind the shower wall where I can never ever retrieve it. I’m sure there’s a way to get a new pin but you can’t turn the water back on until you do so the stakes are high!!

True but the nice thing is if you view it on a 4K display it will be pixel-perfect, so the clarity will be maximized.

I believe that’s a star in our galaxy (Milky Way) so the mirrors/lenses on JWST show the 6-pointed artifact. For things further away (i.e. other galaxies) that doesn’t happen.