POINTABLE OPTICAL SYSTEM WITH COUDE OPTICS HAVING A SHORT ON-GIMBAL PATH LENGTH

摘要

A coude gimbal structure (30) includes a two-axis gimbal system (36) having an outer gimbal (38) pivotable about a first rotational axis (40), and an inner gimbal (42) supported on the outer gimbal (38) and pivotable about a second rotational axis (44) which intersects the first rotational axis (40) at an intersection point (46). A folded afocal three-mirror anastigmat (56) has a positive-optical-power primary mirror (58), a negative-optical-power secondary mirror (60), and a positive-optical-power tertiary mirror (62), and a first flat fold mirror (64), and a second flat fold mirror (66). A beam path (70) incident upon the primary mirror (58) is reflected from the primary mirror (58) to the secondary mirror (60). The tertiary mirror (62) lies on the second rotational axis (44), the first flat fold mirror (64) redirects the beam path (70) reflected from the secondary mirror (60) to the tertiary mirror (62), and the second flat fold mirror (66) lies at the intersection point (46) and redirects the beam path (70) reflected from the tertiary mirror (62) along the first rotational axis (40).