How do you calculate obliquity of ecliptic?

1 Answer
May 19, 2016

Imagine that you are an equatorian (in Brazil), standing at noon on summer solstice (about June 21). Then, tan (obliquity) = h/l, where h is your height and l is the length of your shadow.


At a solstice noon, the angle of incidence of light rays from the Sun upon the equator is (almost) obliquity = #23.4^o#.

If Y is your head, U your foot and US is shadow, #tan angle USY = (YU)/(US)#, and you subtend #angle USY = obliquity, at S..