LaserLiner AL 22 Classic Manual De Instrucciones página 10

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Prior to its use, the instrument should be given time to adopt
the prevailing temperature of the area.
Alignment
1
1. Initial alignment of the telescope towards the graduated
staff is done by hand, using the iron sights.
2. Focus the image of the staff, by operating the focusing knob,
turn crosshairs onto the staff centre.
3. Make sure focusing is free of parallax. The focusing is alright when cross-
hairs and graduation of the staff don't change their positions even when
looked at from different angles (keep changing position of the eye in front
of the eyepiece).
Remaining inclinations of the crosshairs which are left after the
levelling bubble has been centred will be eliminated by the
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compensator. The compensator, however, will not eliminate any
inclinations caused by faulty calibration of the levelling bubble or
the crosshairs. Therefore, the positions of both gadgets should be
checked before measuring (see calibration).
Determination of a height difference
2
1. Place instrument halfway between
the positions of staves A and B.
Aim instrument at staff A and read
the value of the graduation of the
staff at your crosshairs (A = 140 cm).
Turn instrument towards rod B and
get the reading from the graduation
(B = 90 cm).
2. The difference (A-B) results in a
height difference H = +50 cm
between B and A. The point B is 50 cm higher than point A. The difference
H turns negative when point B is lower than point A.
A slight deviation of the crosshairs does not cause any misreadings
!
provided the instrument has been placed approx. midway between
the positions of the two staves A and B.
10 GB
A
½L
B
½ L