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FM 6-50, MCWP 3-1.6.23 b. The procedure for field-expedient declination of the M2 compass is as follows: (1) Using the azimuth adjuster scale, set off the grid-magnetic (G-M) angle (shown on the bottom of all military maps). (2) Once the G-M angle has been set off on the azimuth scale, the M2 compass is declinated. 4-13. MEASURING AN AZIMUTH AND SITE TO CREST WITH THE M2 COMPASS a. The procedure to measure an azimuth follows: To read the azimuth scale by reflection, hold the compass in both hands at eye level with arms braced against body and with the rear sight nearest your eyes. Place the cover at an angle of approximately 45° to the face of the compass (Figure 4-11) so that the scale reflection can be viewed in the mirror. Level the instrument by viewing the circular level in the mirror. Sight on the desired object and read the azimuth indicated on the reflected azimuth scale by the south-seeking (black) end of the compass needle. b. The procedure to measure site to crest follows: Hold the compass on edge with both hands at eye level with arms braced against the body and with the rear sight nearest your eyes. Place the cover at approximately 45° to the face of the compass (Figure 4-11) so that the elevation scale reflection can be seen in the mirror. Sight on the crest of the highest object in the sector of fire. Center the elevation scale tubular level with the lever on the back of the compass and by viewing the elevation scale in the mirror. Read the elevation in mils on the elevation scale. Measure the sight to crest two additional times, and record the average. CAUTION When measuring an azimuth be sure no magnetic materials are near the compass. 4-14. CARE AND HANDLING OF THE M2 COMPASS The M2 compass will not stand rough handling or abuse. Keep the compass in the carrying case (with the mirror side facing in) protected from dust and moisture. Section V LAYING 4-15. PRINCIPLES OF LAYING (1) As was mentioned previously, the aiming circle is the primary means by which the cannon battery orients a. Reciprocal laying is a procedure by which the 0-3200 line of one instrument and the 0-3200 line of another weapons on the azimuth of fire. The aiming circle is used to measure horizontal clockwise angles from the line of fire instrument are laid parallel. To fully understand the principle to the line of sight to a given aiming point. In reciprocal behind reciprocal laying (Figure 4-12, page 4-12) you must laying, the aiming point for the aiming circle is the howitzer first understand several concepts and definitions. panoramic telescope. The pantel is used to measure 4-11 |