If I remember right it was in India that trigonometry was invented. It has just occurred to me that in measuring the height of the sun with the aid of a vertical pole, you measure the length of the horizontal shadow from the pole, and for that you need trigonometry.

Sinus and cosinus, names for the variable lengths measured. I will now return Hancock 3 to the library. But I then happen to note I have made a mistake: the planets (seen from above) do not rotate clockwise but counterclockwise around the sun:

If you see the stars moving westwards across the sky, then that must mean you are turning counterclockwise. Unless you are standing south of the equator. (And what if you are standing on the equator?)