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 229 of 590

5-55

TM 9-1240-401-34&P

6

7

8

9

10

11

Measure distance from cap (5) to mark on wall in

inches (centimeter).

Multiply the distance found in step 6 by 0.30350

(tangent of 300 roils).

Place tape (6) above and below mark, at a dis-

tance determined in step 7.

Rotate elevation knob (7) from stop to stop. The

reticle must follow plumb line (1) within 0.5 mil. The

line of sight must elevate, or depress, no less than

300 roils in each direction from center.

If line of sight travel is not within the 300-mil limits

in each direction, adjust elevation knob (7) (ref.

para 5-13).

If the reticle does not track the plumb line (1) within

0.5 roil, send M117/M117A2 panoramic telescope

to depot for maintenance on dove prism assembly.

i. AZIMUTH ERRORS (800-MIL STEPS) AND BACKLASH (AZIMUTH MECHANISM)

1

2

3

NOTE

Azimuth reading shall be made at 800-mil in-

crements through one full revolution of the

azimuth fixture ring (1) in each direction.

Rotate azimuth fixture ring (1) counterclockwise to

800 mils.

Rotate azimuth knob (2) clockwise until retitles

coincide (ref. para 5-26c). If coincidence point is

overtraveled, rotate azimuth knob (2) counterclock-

wise one-half turn past coincidence point and re-

peat this step.

Azimuth counter (3) should increase by 800 mils

± 1.0 mil and reset counter (4) should increase by

800 roils ± 1.0 mil. Record readings.