Slightly off topic, but I was so surprised how steep the Axial tilt is (http://en.wikipedia.org/wiki/Axial_tilt http://en.wikipedia.org/wiki/Axial_tilt) I had a

Slightly off topic, but I was so surprised how steep the Axial tilt is (http://en.wikipedia.org/wiki/Axial_tilt http://en.wikipedia.org/wiki/Axial_tilt) I had always known that it was 23º but never actually visualized it. Try putting γ=23º in the Euler angles and rotate the earth with λ.