* That would be the September Equinox where the direction of rotation is 'orbital' North West to South East using the East-West orbital plane as a reference -

https://en.wikipedia.org/wiki/Deep_S...-tilt-23.4.gif

http://afewbitsmore.com/img/2015_ecliptic.png

The circle of illumination provides another visible reference and especially using the rotation of the North and South poles along with the entire surface of the Earth parallel to that orbital plane. The most dramatic experience of this is certainly Polar sunrise and sunset where the Sun comes into view or turns out of sight for 6 months at a time at either poles.