Periscopes with compensation for image motion caused by bending

Claim 1

AN OPTICAL VIEWING INSTRUMENT COMPRISING AN ELONGATED CASING HAVING ENTRANCE AND VIEWING ENDS, SUPPORTING MEANS RIGIDLY SUPPORTING SAID CASING INTERMEDIATE SAID ENDS, SAID CASING HAVING A BENDABLE PORTION BETWEEN SAID SUPPORTING MEANS AND SAID ENTRANCE END WHICH IS FREE AND SUBJECT TO BENDING, A TELESCOPE SYSTEM HAVING A PLURALITY OF OPTICAL ELEMENTS SUPPORTED WITHIN SAID CASING IN AXIALLY SPACED RELATION PRODUCING AN IMAGE AT A SELECTED FOCAL PLANE INCLUDING AN OPTICAL ELEMENT AT SAID ENTRANCE END FOR DIRECTING LIGHT RAYS TOWARD SAID SELECTED FOCAL PLANE, SAID OPTICAL ELEMENTS INCLUDING AT LEAST ONE ADJUSTABLE OPTICAL ELEMENT SUPPORTED FOR TILTING MOVEMENT RELATIVE TO THE CASING, A SUBSTANTIALLY RIGID ELONGATED CONTROL MEMBER INTERCOUPLED WITH SAID ADJUSTABLE OPTICAL ELEMENT FOR REGULATING THE ANGULAR POSITION OF SAID ADJUSTABLE OPTICAL ELEMENT, SAID CONTROL MEMBER NORMALLY DISPOSING SAID ADJUSTABLE OPTICAL ELEMENT AT A POSITION TO TRANSMIT EMERGENT RAYS ALONG A NORMAL AXIS TO PRODUCE AN IMAGE AT SAID FOCAL PLANE AT A SELECTED NORMAL IMAGE POSITION WHEN SAID BENDABLE CASING PORTION OCCUPIES A NORMAL UNBENT POSITION, SAID CONTROL MEMBER LYING AT LEAST PARTIALLY WITHIN SAID BENDABLE CASING PORTION, AND A PLURALITY OF AXIALLY SPACED MOUNTING MEANS SUPPORTING SAID CONTROL MEMBER ON SAID CASING INCLUDING MOUNTING MEANS EXTENDING BETWEEN SAID CONTROL MEMBER AND SAID BENDABLE CASING PORTION TO EFFECT TILTING OF SAID CONTROL MEMBER IN RESPONSE TO BENDING MOVEMENT OF SAID BENDABLE CASING PORTION FOR SELECTIVELY TILTING SAID ADJUSTABLE OPTICAL ELEMENT RELATIVE TO THE CASING UPON BENDING OF SAID BENDABLE CASING PORTION TO CONTINUOUSLY DISPOSE SAID ADJUSTABLE OPTICAL ELEMENT AT POSITIONS SUBSTANTIALLY STABALIZING THE IMAGE PRODUCED AT SAID FOCAL PLANE AGAINST DISPLACEMENT FROM SAID NORMAL IMAGE POSITION.