Futech EAGLE 24, Manual

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the bubble in the center (See fig.2) .
∙ Adjust the eyepiece until the image of
the reticle is clear.
∙ Aim the objective at the staff through
the sight gage of the instrument.
∙ Turn the focusing knob to get the
staff image very clear. Shift your eyes
around in the field of view and make
sure that there is no displace between
the reticle and the staff, then the sur-
veying and reading can be done. Ad-
just horizontal fine moving knob to aim
the telescope at the target.
2. Surveying method
2.1. Measuring altiitude difference
∙ Set up the instrument at a point ap-
proximately halfway between points A
and B. (See fig.3)
∙ Set up the staff vertically at point A,
and take the reading a (backsight).
∙ Set up the staff vertically at point B,
and take the reading b (foresight).
∙ The altitude difference h from B to A is
h = a − b.
∙ If the distance between A and B is too
long, or the altitude difference from
B to A is too large, divide the distance
into some regions, then carry on meas-
Fig. 3:
Fig. 2: