Doug,
If you lived 1000 years ago, in temperate latitudes, you would see the
sunrise and sunset azimuths move closer together as the winter solstice
approached.
They would then stop and move apart again.
Knowing nothing about why this happened, you would worry in case one
year they kept going and you would be left in permanent darkness.
To check, you would set up standing stones as markers for reassurance.
You might also set other stones to mark the summer solstice and even the
equinoxes.
If you counted the days between the recurrence of identical events over
several decades (requires recording of information across generations)
you would eventually come to the 365.25 figure.
But why are you choosing 1000 years ago?
The Egyptians knew this way before, because they had to be able to
predict the Nile Floods.
I understand that they used Sirius rising as their marker.
Mike Shaw
53º22'N 3º02'W
---------------------------------------------------
https://lists.uni-koeln.de/mailman/listinfo/sundial
