Move Z until: - arc(Spring-Summer) measures aprox. 93.1 degrees; - arc(Summer-Autumn) mearures aprox. 91.2 degrees; - arc(Autumn-Winter) measures aprox. 86.9 degrees; - arc(Winter-Spring) measures aprox. 88.8 degrees.
When all conditions are respected: - what is the lenght of [ZT]? - what is the ratio between 60 and the lenght of [ZT]?