TM-9-1240-401-34&P Technical Manual for M109 Telescopes and Mounts Download
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TM 9-1240-401-34&P 5-53 f. IMAGE TILT ADJUSTMENT 1 2 3 4 5 6 7 8 9 Position pre-plumbed collimating projector (1) at level of window in cap (2) of M117/M117A2 pano- ramic telescope so that the two optical axes lie in parallel planes. Check image tilt through one full revolution of the cap (2) in each direction. The image of the vertical reticle line shall be vertical within 2° (0.62 mils) of arc. This requirement shall also be met with the elbow assembly positioned against each of the swing stops at each azimuth setting. If image tilt is not within specified limits, remove three machine screws (3) and access cover (4). Remove setscrew (5) from shaft (6). Insert hexagon key into center of shaft (6) and turn until image of the vertical reticle line is within 2° (0.62 mils) of arc. (Ref. TM 9-254 for conversion to roils.) Remove hexagon key and replace setscrew (5). Be careful not to disturb established position. Recheck image tilt as directed in steps 1 and 2. If necessary, repeat steps 4,5, and 6. Install access cover (4) and secure with three machine screws (3).