[sawjet]

The first 'observatory' was a stick placed vertically in the ground such that it's shadow traced the angular relationship of the sun & earth

[pmontra]

And in one year of observations they noticed that the point of the stick followed an 8 shaped track on the ground. I wonder what they thought about it.

I attempted to build a naive sundial last year and I was surprised when I saw the sun moving east to west (or vice-versa, can't remember) at the same hour. It's very noticeable week over week.

https://en.wikipedia.org/wiki/Analemma

If only we had a perfectly circular orbit and no axial tilt!