©2009 Johnson Level & Tool
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Keep about half the length engaged. When the bubble is centered in posi-
tion #1, turn the instrument and observe the vial in position #2. Now cen-
ter the bubble in position #2 using only screw C. The instrument should
now be leveled, but to be certain, double-check. Rotate the instrument
180º so the vial is reversed. If the bubble will not center when reversed,
follow adjustment procedure outlined under “Bubble Adjustments.”
Aiming and Focusing
Rotate the instrument by hand to aim the telescope to the far object.
Rotate the focusing knob until the object can be observed clearly.
Rotate the horizontal tangent knob, to place the vertical cross hairs
on the object.
Reading the Vernier
The vernier is actually a double
vernier, that is, two verniers in
one. This makes it possible to
read any angle turned by the
telescope, whether to the right
or to the left. For example,
consider that you have turned
an angle to the left (counter-
clockwise) after first having set the circle to read 0º. Refer to the
bottom figure, this is what your vernier looks like after having turned
the angle.
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