In the second workshop, you considered the situation where the x-axis is aligned due North, the y-axis due West, the z-axis vertically upwards and a single, unrotated mirror is located at the origin of the xyz-coordinate system with its normal m^ pointing due North, that is, m^
=(1,0,0). Recall that, if the mirror is rotated counter-clockwise by an angle ψ about an axis aligned with the z-axis followed by an angle θ about the horizontal axis of the mirror (this axis coincided with the y-axis in the zero position of the mirror, but has now been rotated by an angle ψ ), then the new unit normal
n^ to the mirror is related to the starting unit normal m^ via n^ =(cos(ψ)cos(θ),sin(ψ)cos(θ),−sin(θ))