Patent ID: 7556389

Claim:
A coude gimbal structure comprising: a two-axis gimbal system including an outer gimbal pivotable about a first rotational axis, and an inner gimbal supported on the outer gimbal and pivotable about a second rotational axis which is perpendicular to the first rotational axis and which intersects the first rotational axis at an intersection point; and a folded afocal three-mirror anastigmat having a positive-optical-power primary mirror, a negative-optical-power secondary mirror, and a positive-optical-power tertiary mirror, a first flat fold mirror, and a second flat fold mirror, wherein the primary mirror and the secondary mirror lie on a third axis passing through the intersection point and lying perpendicular to the first rotational axis and perpendicular to the second rotational axis, and wherein a beam path parallel to the third axis is reflected from the primary mirror to the secondary mirror, the tertiary mirror lies on the second rotational axis, the first flat fold mirror redirects the beam path reflected from the secondary mirror to the tertiary mirror, and the second flat fold mirror lies at the intersection point and redirects along the first rotational axis the beam path reflected from the tertiary mirror.