# Axis of rotation of the earth

It is known that the axis of rotation of earth is tilted with respect to the perpendicular to the plane of orbit. Is there a way to measure this tilt from earth without the aid of pictures taken from space?

• You can measure the highest latitude at which the sun ever appears directly overhead. – The Photon Apr 15 at 4:55
• Thats an answer – Jasper Apr 15 at 5:34
• @Jasper, I assume it can be done with observations from anywhere and a little math, so I'm hoping someone will give an answer showing how to do it without traveling to the tropics. – The Photon Apr 15 at 5:45

## 2 Answers

there are many ways to calculate the angle of axis of the earth.

One way is to measure the sun's angle on the day between spring and autumnal Equinox, usually 90 days in between the two.

Because the axis of earth rotation is in a perpendicular to plane of orbit of the earth around the sun at that moment and with correct inclination, this angle is equal to observers latitude plus or minus the earth axis, depending on witch hemisphere they are. If they measure this from the equator it is the angle of earth's axis.

I guess it would be possible to measure the tilt by finding the position the sun would be at the highest position between six months when the angle is highest and lowest at a particular place. I will try to attach a diagram if possible.