TUBE LEVELS. KNOB COVER. ORIENTING KNOB. NOTATION PAD. USMC

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WELCOME TO THE M2A2 AIMING CIRCLE
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FOUR MAJOR PARTS OF AN AIMING CIRCLE
TELESCOPE ASSEMBLY
BODY ASSEMBLY
WORM GEAR HOUSING
BASE PLATE ASSEMBLY
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COMPONENTS OF THE M2 AIMING CIRCLE
AIMING CIRCLE COVER
STRAP
CATCH ASSEMBLY
BASE PLATE
BASE PLATE COVER
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M24 TRIPOD
LEG STRAP
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ACCESSORY KIT
CANVAS COVER
BACK PLATE
INSTRUMENT LIGHT
BULB EXTRACTOR PLUMB BOB
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SETTING UP THE TRIPOD
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• UNSTRAP THE LEGS OF THE TRIPOD
• LOOSEN THE LEG CLAMP THUMBSCREWS AND EXTEND THE
  LEGS TO THE APPROX. SHOULDER HEIGHT
• TIGHTEN THE LEG CLAMP THUMBSCREWS

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• PLACE THE TRIPOD OVER THE POINT TO BE OCCUPIED,
  WITH ONE TRIPOD LEG BISECTING THE AREA OF
  INTEREST
• ROUGH LEVEL THE TRIPOD BY LOOKING OVER THE TOP
  OF THE TRIPOD HEAD
• FIRMLY PRESS EACH LEG INTO THE DECK WITH YOUR
  BOOT

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ATTACH THE AIMING CIRCLE TO TRIPOD

• PULL BACK THE SPRING-LOADED COVER ON THE BASE OF
  THE BASE PLATE, AND PLACE THE AIMING CIRCLE ON
  THE TRIPOD. LOOSELY SCREW THE INSTRUMENT-FIXING
  SCREW INTO THE BASE PLATE.
• CENTER THE PLUMB BOB OVER THE ORIENTING STATION
  BY MOVING THE BASE PLATE OF THE AIMING CIRCLE.
  THE PLUMB BOB SHOULD BE APPROXIMATELY 1 INCH
  ABOVE THE STATION MARKER.
• TIGHTEN THE INSTRUMENT-FIXING SCREW INTO THE BASE
  PLATE OF THE AIMING CIRCLE, AND REMOVE THE PLUMB
  BOB

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-CAUTION- DO NOT OVERTIGHTEN THE INSTRUMENT
FIXING SCREW OR THE SLOTTED ARM WILL DAMAGE THE
THREADS IN THE TRIPOD HEAD
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• REMOVE THE AIMING CIRCLE HEAD COVER, AND HANG IT
  ON THE TRIPOD HEAD COVER TO PREVENT DAMAGE

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LEVELING THE AIMING CIRCLE
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• ADJUST LEVELING SCREWS SO YOU CAN SEE 3/8 TO
  1/2 INCH OF THREAD
• UNCOVER THE LEVELING VILE
• PULL THE AZIMUTH MICROMETER KNOB SLIGHTLY TO
  THE REAR TO RELEASE THE LOCK AND ROTATE THE
  AIMING CIRCLE UNTIL THE LEVELING VILE IS PARALLEL
  TO ANY 2 OF THE LEVELING SCREWS
• ENSURE THE GEARS LOCK

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• TO LEVEL THE BUBBLE IN THE FIRST POSITION, TURN
  BOTH SCREWS AT THE SAME TIME EITHER TOWARD EACH
  OTHER, OR AWAY FORM EACH OTHER UNTIL THE BUBBLE
  MOVES TO THE CENTER.
• THE BUBBLE MOVES IN THE SAME DIRECTION AS YOUR
  LEFT THUMB

OR
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1. MOVE TO THE SECOND LEVELING POSITION, TURN
THE AIMING CIRCLE HEAD SO THAT LEVELING VILE IS
AT A RIGHT ANGLE TO THE FIRST POSITION 2. TO
CENTER THE BUBBLE IN THE SECOND POSITION, USE
ONLY THE REMAINING LEVELING SCREW 3. GO BACK AND
FORTH BETWEEN POSITIONS MAKING FINE ADJUSTMENTS
UNTIL THE BUBBLE REMAINS CENTERED IN BOTH
POSITIONS
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MEASURING HORIZONTAL ANGLES
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HORIZONTAL ANGLES SETUP ON REAR STATION

• SET ALL SCALES TO ZERO
• OPEN ORIENTING KNOB COVERS, PULL KNOB BACK
  SLIGHTLY TO RELEASE THE LOCK
• ROTATE THE CIRCLE HEAD SO THAT IT IS POINTED
  JUST LEFT OF THE REAR STATION, RELEASE THE
  ORIENTING KNOB AND INSURE THAT IT LOCKS INTO
  POSITION

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• LOOK THROUGH THE TELESCOPE AND TURN THE
  ORIENTING KNOBS TOWARD YOU TO BRING THE VERTICAL
  CROSSHAIR TO THE CENTER OF THE REAR STATION. THE
  LAST MOTION SHOULD BE FROM LEFT TO RIGHT. CLOSE
  THE COVERS ON THE ORIENTING KNOBS
• TURN THE ELEVATION MICROMETER UNTIL THE
  HORIZONTAL CROSSHAIR IS AT THE LOWEST VISIBLE
  POINT ON THE REAR STATION.

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1. PULL THE AZIMUTH MICROMETER KNOB SLIGHTLY TO
THE REAR, ROTATE THE AIMING CIRCLE TO BRING THE
VERTICAL CROSSHAIR JUST LEFT OF THE FORWARD
STATION. ROTATE THE AZIMUTH MICROMETER CLOCKWISE
UNTIL IT LOCKS INTO POSITION. 2. TURN THE
ELEVATION MICROMETER UNTIL THE HORIZONTAL
CROSSHAIR IS AT THE LOWEST VISIBLE POINT OF THE
FORWARD STATION. 3. TURN THE AZIMUTH MICROMETER
KNOB CLOCKWISE UNTIL THE VERTICAL CROSSHAIR IS
CENTERED ON THE FORWARD STATION. YOUR LAST
MOTION IS FROM LEFT TO RIGHT.
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READ AND RECORD THE HORIZONTAL ANGLE
1. TO DETERMINE THE HORIZONTAL ANGLE, FIRST READ
THE AZIMUTH SCALE. EACH MARK IS 100 MILS. 2.
THEN READ THE AZIMUTH MICROMETER SCALE. EACH
MARK IS ONE MIL. COMBINE THE READINGS TO GET THE
HORIZONTAL ANGLE. FOR EXAMPLE, THIS READING IS
0655.5 MILS. WHEN YOU MEASURE, ROUND OFF TO THE
NEAREST ½ MIL. RECORD THIS READING.
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HORIZONTAL ANGLES TURN CHECK ANGLE
1. LEAVE FIRST ANGLE ON AZIMUTH SCALES 2. OPEN
ORIENTING KNOB COVERS, PULL ORIENTING KNOB BACK
SLIGHTLY TO RELEASE THE LOCK 3. ROTATE THE
AIMING CIRCLE HEAD SO THAT THE AIMING CIRCLE IS
POINTED JUST LEFT OF THE REAR STATION, RELEASE
THE ORIENTING KNOB AND INSURE THAT IT LOCKS INTO
POSITION
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HORIZONTAL ANGLES SETUP ON REAR STATION
1. LOOK THROUGH THE TELESCOPE AND TURN THE
ORIENTING KNOBS TOWARD YOU TO BRING THE VERTICAL
CROSSHAIR TO THE CENTER OF THE REAR STATION.
YOUR LAST MOTION SHOULD BE FROM LEFT TO RIGHT.
CLOSE THE COVERS ON THE ORIENTING KNOBS 2. TURN
THE ELEVATION MICROMETER UNTIL THE HORIZONTAL
CROSSHAIR IS AT THE LOWEST VISIBLE POINT ON THE
REAR STATION
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HORIZONTAL ANGLE TURN CHECK ANGLE
1. PULL THE AZIMUTH MICROMETER KNOB SLIGHTLY TO
THE REAR, ROTATE THE AIMING CIRCLE TO BRING THE
VERTICAL CROSSHAIR JUST LEFT OF THE FORWARD
STATION. ROTATE THE AZIMUTH MICROMETER CLOCKWISE
UNTIL IT LOCKS INTO POSITION. 2. TURN THE
ELEVATION MICROMETER UNTIL THE HORIZONTAL
CROSSHAIR IS AT THE LOWEST VISIBLE OF THE FORWARD
STATION. 3. TURN THE AZIMUTH MICROMETER KNOB
CLOCKWISE UNTIL THE VERTICAL CROSSHAIR IS
CENTERED ON THE FORWARD STATION. YOUR LAST
MOTION IS FROM LEFT TO RIGHT.
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READ AND RECORD THE CHECK ANGLE

• TO DETERMINE THE HORIZONTAL ANGLE, FIRST READ THE
  AZIMUTH SCALE. EACH MARK IS 100 MILS
• THEN READ THE AZIMUTH MICROMETER SCALE. EACH
  MARK IS ONE (1) MIL. COMBINE THE READINGS TO GET
  THE HORIZONTAL ANGLE
• EXAMPLE THIS READING IS 0655.5 MILS. WHEN YOU
  MEASURE, ROUND OFF TO THE NEAREST ½ MIL.
• RECORD THIS READING

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DETERMINE THE MEAN ANGLE
HORIZONTAL ANGLE 0862.0 CHECK ANGLE
1724.0

• CHECK ANGLE DIVIDED BY 2 MUST AGREE WITH
  HORIZONTAL ANGLE WITHIN ½ A MIL
• IF NOT, START OVER AND TURN THE ANGLE AGAIN
• IF THE CHECK ANGLE IS LESS THAN THE HORIZONTAL
  ANGLE, ADD 6400 AND THEN DIVIDE BY 2

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MEASURING VERTICAL ANGLES
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1. TO DETERMINE THE VERTICAL ANGLE, FIRST READ
THE ELEVATION SCALE. EACH NUMBER IS 100 MILS. THE
BLACK NUMBERS ARE POSITIVE (), THE RED NUMBERS
ARE NEGATIVE (-). 2. THEN, READ THE ELEVATION
MICROMETER SCALE. EACH MARK IS ONE MIL. COMBINE
THE READINGS TO GET THE FIRST VERTICAL ANGLE. FOR
EXAMPLE, THIS READING IS 0105 MILS. WHEN YOU
MEASURE, ROUND OFF TO THE NEAREST .5 MIL.
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WHAT IS THE VERTICAL ANGLE SHOWN BELOW?
A. 94 MILS B. 86 MILS C. -26 MILS D.
-14 MILS
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WHAT IS THE VERTICAL ANGLE SHOWN BELOW?
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DECLINATING THE AIMING CIRCLE
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• MAGNETIC NORTH VARIES WIDELY IN DIFFERENT
  REGIONS OF THE PLANET DUE TO MASSIVE ORE DEPOSITS
  UNDER THE EARTHS SURFACE
• CORRECTING FOR THESE DIFFERENCES IS DONE USING
  A PROCESS CALLED DECLINATION WITH THE END RESULT
  BEING A DECLINATION CONSTANT
• THE DECLINATION CONSTANT IS A VALUE APPLIED TO
  THE SCALES OF THE AIMING CIRCLE TO CHANGE
  MAGNETIC AZIMUTHS TO GRID AZIMUTHS IN YOUR LOCAL
  OPERATIONAL AREA

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DECLINATING THE AIMING CIRCLE

• SETUP THE AIMING CIRCLE OVER A DECLINATION
  STATION AND LEVEL THE INSTRUMENT
• UTILIZING THE RECORD KNOB(UPPER MOTION) SET
  KNOWN AZIMUTH
• UTILIZING THE NON-RECORD KNOB(LOWER MOTION)
  SIGHT ON AZIMUTH MARKER
• WITH THE RECORD KNOB AGAIN, SIGHT THE ELBOW
  TELESCOPE IN GENERAL DIRECTION OF NORTH
• ref 6-50, pg
  2-1

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DECLINATING THE AIMING CIRCLE

• UNLOCK MAGNETIC COMPASS NEEDLE
• TURN THE RECORD KNOB UNTIL MAGNETIC COMPASS
  NEEDLE IS CENTERED ON THE MIDDLE RETICLE. LOOK
  THROUGH MAGNIFIER. READ DECLINATION CONSTANT
  DIRECTLY FROM AZIMUTH SCALE(NEAREST .5 MIL).
• RECORD THIS INDICATION. REPEAT THIS PROCESS AND
  RECORD THE AVERAGE
• Note ALL THE INDICATIONS MUST BE WITHIN /-2
  MILS OF EACH OTHER.
• ref 6-50, pg 2-1

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OCCASIONS FOR DECLINATION

• EVERY THIRTY DAYS
• AFTER SEVERE ELECTRICAL STORMS
• AFTER BEING DROPPED
• AFTER INITIAL ISSUE OR UPON RETURN FROM
  MAINTENANCE
• AFTER MOVEMENT OF MORE THAN 40KM OR 25 MILES FROM
  LAST DECLINATION POINT

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ORIENT THE AIMING CIRCLE TO GRID NORTH
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(1) READ THE DECLINATION CONSTANT FROM THE
NOTATION PAD (2) USE THE UPPER (RECORDING)
MOTION TO SET THE DECLINATION CONSTANT ON THE
AZIMUTH AND AZIMUTH MICROMETER SCALES
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ORIENT THE AIMING CIRCLE TO GRID NORTH

• (3)UNLOCK THE MAGNETIC NEEDLE
• LOOK IN THE WINDOW ON TOP OF THE AIMING CIRCLE
  MAIN BODY
• USE THE LOWER (NON-RECORDING) FAST MOTION TO
  ROTATE THE AIMING CIRCLE HEAD UNTIL THE MAGNETIC
  NEEDLE MOVES TO CENTER OF THE WINDOW.

MAGNETIC NEEDLE
LOCKING LEVER IN UNLOCKED POSITION
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ORIENT THE AIMING CIRCLE TO GRID NORTH
(6) LOOK INTO THE MAGNIFIER AND CENTER THE
HAIRLINE ON THE WHITE AREA ON THE END OF THE
MAGNETIC NEEDLE USING THE ORIENTING KNOB (7)
LOCK MAGNETIC NEEDLE (8) THE AIMING CIRCLE IS
NOW ORIENTED AND CAN BE USED TO MEASURE GRID
AZIMUTHS
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QUESTIONS