CAUTION
(3) Close the battery box (9, fig. 2-1) and
mount the box on the tripod (11). Push the knob on
Conserve the life of the batteries by
the lower end of the battery box to the left to open
a d v a n c i n g the rheostat knob only to a
the cover over the two connector receptacles in the
position which provides sufficient
lower end of the battery box (9). Insert one battery
illumination for operation of the in-
cable connector plug (12) in the receptacle farthest
strument. Advance the setting of the
from the release knob. Insert the connector plug on
knob as may be
required by the ageing
the other end of the battery cable in the inner base
o f the batteries.
housing receptacle (14).
(1) Remove the
connector plug (15, fig. 2-1)
( 4 ) Insert the hand lamp connector plug (10)
o f the plug-in lamp
from the alidade connector
in the battery box receptacle nearest the receptacle
receptacle (6). Loosen
the mounting screw (17) and
cover release knob. Hang the hand lamp (13) on
remove the plug-in lamp and reflector from the
t h e tripod head cover. Lighting the hand lamp is
instrument.
controlled by the ON-OFF switch located on the
(2) Remove the hand lamp cable connector
s i d e of the hand lamp case.
p l u g (10) from the battery box (9) and remove the
(5) Make sure that the combination switch
hand lamp (13) from the tripod head cover.
and rheostat knob (8) is turned to its extreme
(3) Remove the connector plugs (7 and 12)
counterclockwise position.
from the inner base housing receptacle (14) and the
( 6 ) Position the plug-in lamp (16) and plug-in
connector receptacle of the battery box (9).
lamp reflector (18) on the theodolite left side cover
(4) Remove the battery box (9) from the
F a s t e n the plug-in lamp assembly to the left side
t r i p o d (11). Open the battery box and replace the
cover by screwing the mounting screw (17) into the
plug-in lamp and hand lamp assemblies. Fasten the
threaded mounting nut (8, fig. 2-4).
battery box cover.
( 5 ) Replace the illumination mirror assembly
( 7 ) Insert the connector plug (15, fig. 2-1) of
(6, fig. 1-2).
the plug-in lamp cable in the alidade connector
receptacle (6).
(8) Turn the switch and rheostat knob (8) in a
clockwise direction until the desired degree of
illumination is obtained on both circles, the
horizontal circle level, and the vertical circle level.
Section
III.
OPERATION
UNDER
UNUSUAL
CONDITIONS
to use. Snowfall, winds, and refraction of light are
2-31. General
some of the difficulties encountered under low
Most surveying must be done when weather and
temperature
conditions.
terrain conditions are not ideal. Rough terrain,
CAUTION
d e n s e undergrowth, and unstable ground surfaces
Avoid
subjecting
the
theodolite
to
add to the surveyor's problems. Other factors which
s u d d e n changes in temperature.
hinder include wide temperature variations,
humidity, wind currents, and excessive sunlight.
2-33. Operation in Extreme Heat
S u c h conditions necessitate the taking of shorter
The theodolite and instrument man should be
s i g h t s , greater diligence in making readings, and
protected by a surveyor's umbrella when sights
more maintenance must be given the theodolite.
h a v e to be taken in direct sunlight. Direct rays of
2-32. Operation in Extreme Cold
the sun can cause internal stresses and distortion in
t h e instrument. Heat waves produce poor sighting
With
proper
precautions
and
servicing,
the
c o n d i t i o n s . Long sights increase, and short sights
t h e o d o l i t e can be used in extreme cold. Its use is
decrease, the amount of sighting errors. Taking
only limited by the endurance of operating per-
sights during the cooler early morning and late
sonnel and conditions affecting visibility. The
evening will also minimize error magnitude. The
instrument should be kept out of doors or in
use of suitable dark glasses by the instrument man
unheated buildings for short periods of non-use.
will reduce eye strain and fatigue. If the theodolite
Extreme changes in temperature will induce in-
is kept in a cool storage place, it should be brought
t e r n a l stresses affecting accuracy, and lenses and
out of storage some time before use to allow metal
p r i s m s may become fogged. Theodolites to be used
t e m p e r a t u r e to approach that of the outside air.
under conditions of extreme cold should be cleaned
and all possible lubricant removed before being put
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