surveying iii (topographic and geodetic surveys) - Modern Prepper

(2) When adjusting the lamp's height, point the center of the most brilliant part of the beam to theobserver. If the sights are used in pointing, they must be parallel to the light beam. To adjust the sightsby night, point the light to some object near enough to outline the central bright beam. After looseningthe knurled nut, which holds the rear sight bracket, adjust it so that the sights point to a spot as far abovethe center of the beam as the sights above the center of the reflector. Tighten the nuts to hold the bracketand sight in that position. To adjust the sights during the day, place a stake in the ground in the path ofthe light and make a mark on the stake at the point where the reflector shows the brightest. This pointmay be found by moving the eye up and down and sidewise just back from the stake, in the same manneras when focusing the light. Adjust the rear sight so that the sights point to a spot the same distanceabove the mark on the stake as the sights are above the center of the reflector. Adjustments for the focusand sights may be made at the same time.(3) Ensure that the adjustments are properly made, and the bright beam of the light goes to theobserver (if the sights are pointed at him). At night, the pointing may be made over the observer's lightby sighting accurately along the beam from directly above it for line measurements and from the side forelevation measurements. A light not properly pointed may either be invisible to the observer or maycause errors in the observing that may not be detected until all of the stations of the triangle have beenoccupied. This could cause great delay and expense.(4) Be sure to point the light accurately. If at any time there is reason to believe that you mayhave disturbed the pointing of the lights, make the necessary adjustments, starting with the bottom light.Repoint accurately, both horizontally and vertically. Watch the pointings closely on windy nights, as aviolent gust of wind could cause changes.h. Lamp Condition. Keep the lamps in good condition and the reflectors polished. A dull reflectormay result in a misread message. Never use a heater of any kind on the tower or stand, as heat wavesfrom the heater will cause the light to appear wavy to the observer. Never light a lantern or fire aroundthe tower or stand while observing, as the light may easily be mistaken by the observer as a signal light.2-59. Wooden Signal Stands. Wherever elevation and unobstructed lines of sight permit, 4-foot signalstands are used to provide stability of signals for short-line triangulation and mountain areas. They areeasily constructed in a minimum amount of time, easily transported to stations difficult to reach, andstable for observations. The design and construction details for a typical 4-foot stand are shown inFigure 2-16, page 2-44.2-43 EN0593