AT M2 aberrations

sect:ctb-1-1-7-pupil-plane-optics-02

M2 is the pupil plane, and the beam wander should be very small.

Property	Value
Beam diameter	?
Beam walk	? $\mbox{ mm arcsec}^{-1}$
Surface roughness	?
Beam diameter	$138/mbox{ mm}$