Expert: Jayendra Upadhye - 4/24/2007

Question
How did people first find what degrees the earth's axis is tilted out.  

Answer
Hi, Joe,
To get the answer straight from the "horse's mouth", see this link.
http://en.wikipedia.org/wiki/Axial_tilt

However, egyptians and hindus who kept astronomical records over waste stretches of time, even knew about the precession of the equinoxes, or the periodic wandering of the axis (poles) with respect to the stars. (something like a gyrating top).

that link is here..
http://en.wikipedia.org/wiki/Precession_of_the_equinoxes

The link as per "standard" thinking attributes the discovery to hipparchus.
But the hindu epics mention the fact at many places!
And also mention stellar / asterism combinations as observed many thousands of years ago..before human historical times!

A lot many links to astronomy in the epics is also on the web.

But it only means humans have been aware of the axial tilt and its wandering for a long long time than we care to admit.

The dogon sirius myth is a curiosity along the same lines.

Oops! The "How" part! It is in the first link.

But when people maintain observational records over extended periods of time, these things do show up.

Jayen