Look - I appreciate ALL the precision and calculations and everything, but sometimes, a GOOD simple sundial DESIGN ought to be considered for those of use who want to keep track of time in the morning sun when reading a book, without having to do MORE calculations just to use it. Come this equinox, I will have a big aluminium plate, tilted to the mid winter angle of the sun above the horizon - or to make it sit on a simple pivot with a wedge or some thing to tilt it for this latitude, and with a short blunt rod poking out of one side... and when the sun moves around, I will mark that spot with a pointy permanent marker and then at the end of the day, I will drill a small hole through it....

I might even scribe and then chisel in a few lines etc...

That is good enough for more than most people.

If people could see them as FUNCTIONAL time pieces rather than astrolabe interstellar calculation engines - anyway I know what I mean....

I am tired, I don't want to do a whole heap of calculations and design work...

I just want to follow the shadow of the tip of the pointer around, with a centre punch and number stamps...

And the equinox dates - that averages out close enough for me.