Optical Design for Off-axis Two Mirror Collimator

Design process of large pupil,long focus off-axis two-mirror collimator was introduced.The equation of system initialization structure was given.And the disadvantage of coaxal design method was analysised.A design method for off-axis secondary mirror was proposed.When secondary mirror were rotate on main mirror focus,system performance could be improved.The off-axis design method of secondary mirror was proved throught a example.