(2) When adjusting the lamp's height, point the center of the most brilliant part of the beam to
the observer. If the sights are used in pointing, they must be parallel to the light beam. To adjust the
sights by night, point the light to some object near enough to outline the central bright beam. After
loosening the knurled nut, which holds the rear sight bracket, adjust it so that the sights point to a spot as
far above the center of the beam as the sights above the center of the reflector. Tighten the nuts to hold
the bracket and sight in that position. To adjust the sights during the day, place a stake in the ground in
the path of the light and make a mark on the stake at the point where the reflector shows the brightest.
This point may be found by moving the eye up and down and sidewise just back from the stake, in the
same manner as when focusing the light. Adjust the rear sight so that the sights point to a spot the same
distance above the mark on the stake as the sights are above the center of the reflector. Adjustments for
the focus and 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 the
observer (if the sights are pointed at him). At night, the pointing may be made over the observer's light
by sighting accurately along the beam from directly above it for line measurements and from the side for
elevation measurements. A light not properly pointed may either be invisible to the observer or may
cause errors in the observing that may not be detected until all of the stations of the triangle have been
occupied. 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 may
have 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 a
violent gust of wind could cause changes.
h. Lamp Condition. Keep the lamps in good condition and the reflectors polished. A dull reflector
may result in a misread message. Never use a heater of any kind on the tower or stand, as heat waves
from the heater will cause the light to appear wavy to the observer. Never light a lantern or fire around
the 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 signal
stands are used to provide stability of signals for short-line triangulation and mountain areas. They are
easily constructed in a minimum amount of time, easily transported to stations difficult to reach, and
stable for observations. The design and construction details for a typical 4-foot stand are shown in
Figure 2-16, page 2-44.
2-43
EN0593
Previous Page
