You know, there is another data point from the FLIR that undermines the optical effect theory: the relative position to the tracking aircraft.
At the top of the FLIR screen is a measure of the orientation of the FLIR to the aircraft. It starts out (IIRC) at about 4 degrees right of the aircraft. The aircraft itself maintains a relatively stable hold at heading 249-251 (a little south of west) and altitude of 20k. Yet, the FLIR lock rotates (unsteadily) from just right of the aircraft to just left of the aircraft. The movement of the target does not appear to correlate with any change in heading of the aircraft. The 2 appear independent.
At the top of the FLIR screen is a measure of the orientation of the FLIR to the aircraft. It starts out (IIRC) at about 4 degrees right of the aircraft. The aircraft itself maintains a relatively stable hold at heading 249-251 (a little south of west) and altitude of 20k. Yet, the FLIR lock rotates (unsteadily) from just right of the aircraft to just left of the aircraft. The movement of the target does not appear to correlate with any change in heading of the aircraft. The 2 appear independent.