Full article: Solar tracking system – a review
1.1. Solar geometry and solar angles. The earth''s orbit about the sun is almost circular at an average distance of 149.6 million km. The earth''s axis of rotation is tilted by an angle ε = 23.441° with respect to the normal to the plane of the earth''s orbit (Figure 1) (Mitton Citation 1977).The plane of the earth''s orbit is named as the plane of the ecliptic.