TM 5-6675-329-13 & P
+ 15 minutes of arc (1)
+ 0.3 seconds of arc (")
Sensitivity per 2 mm
8 minutes of arc, or (1)
Section III: PRINCIPLES OF OPERATION
The principle of operation of the self-leveling Automatic Level NA2-80 is based on a compensating element containing a
prism which establishes a horizontal line of sight by correcting the light path of an unleveled instrument. Beyond the
range of automatic adjustment, the level can be manually adjusted to a centered-bubble condition.
To check the operation of the compensator, a test pushbutton is incorporated in the level. When momentarily pressed,
the pushbutton moves the compensator off-center. A functioning compensator will swing around the level position and
then automatically return to it.
For surveying purposes, an adjustable focus telescope has been made an integral part of the level. The level also
contains a horizontal drive mechanism which allows it to be turned in the horizontal plane.