TM-9-1240-401-34-P

TELESCOPE MOUNT M146: M118A2 AND M118A3; TELESCOPE MOUNT M145: M145A1; PANORAMIC TELESCOPE: M117 AND M117A2; FIRE CONTROL QUADRANT: M15; PERISCOPE: M42

TECHNICAL MANUAL; DIRECT SUPPORT AND GENERAL SUPPORT MAINTENANCE MANUAL

JULY 1993

TM-9-1240-401-34-P - Page 108 of 590

3-50

TM 9-1240-401-34&P

3-29. M118A2/M118A3 ELBOW TELESCOPE FINAL INSPECTION AND ADJUSTMENT

- continued

c. PARALLAX ADJUSTMENT

1

2

3

4

5

6

View through M118A2/M118A3 elbow telescope

eyepiece (1) and move head from side to side. Ap-

parent movement between telescope reticle

crosslines and target image should not exceed

0.15 mil (the width of reticle line) as measured on

collimating projector (2) reticle.

If error exists, remove setscrew (3).

Using 2 and 2-1/64 inch tubular spanner wrench

(Item 33, appx F), remove cell assembly (4).

Using 1-7/16 and 1-29/64 inch tubular spanner

wrench (Item 30, appx F), make adjustment to cell

(5) by rotating cell (5) until reticle crosslines are

parallel.

Install cell assembly (4) using 2 and 2-1/64 inch

tubular spanner wrench (Item 33, appx F).

Install setscrew (3).

d. EYEPIECE FOCUS ADJUSTMENT

1

2

3

4

5

6

7

8

Rotate eyepiece of dioptometer (1) until reticle

lines of dioptometer are in sharp focus.

Place dioptometer (1) in front of M118A2/M118A3

elbow telescope eyepiece (2).

Look through dioptometer (1) and slide dioptometer

objective back and forth until M118A2/M118A3 el-

bow telescope reticle lines appear sharp and clear.

Remove dioptometer (1), without disturbing its set-

ting, and note reading on side of dioptometer. Eye-

piece focus, as indicated on dioptometer (1),

should be-0.75 to-1.0 diopter.

If error exists, remove setscrews (3 and 4) from

eyepiece arm.

Make adjustment to cell assembly through hole

where larger setscrew (4) was removed.

Recheck eyepiece focus.

Install setscrews (3 and 4). Do not overtighten.