Fun. It reminded me of the https://en.wikipedia.org/wiki/Clock_of_the_Long_Now, which uses a similar noon-sun mechanism for keeping the daily clock cycle accurate.

My neck of the woods on the front page!

Adelsnäs where the cannon is was built by some mining baron, as far as i remember.

Why would a cannon be used instead of, say, striking a bell? Does the sound travel better/further, or was it a display of wealth/status?

But the sun isn't always at the same place at noon? So how is the magnifying glass aimed?