Optical sine theorem

In optics, the optical sine theorem states that the products of the index, height, and sine of the slope angle of a ray in object space and its corresponding ray in image space are equal. That is:

${\displaystyle n_{0}y_{0}a_{0}=n_{i}y_{i}a_{i}}$

• http://physics.tamuk.edu/~suson/html/4323/aberatn.html#Optical%20Sine