Off-axis or unobscured systems in which not all of the mirrors share

Official title: {off-axis or unobscured systems in which not all of the mirrors share a common axis of rotational symmetry, e.g. at least one of the mirrors is warped, tilted or decentered with respect to the other elements}

G02B17/0642 (Off-axis or unobscured systems in which not all of the mirrors share) appears on 98 US grants and 94 published applications in this corpus.