KERN OLM 171, User Instructions

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15 OLM-1-BA-e-1610
5.2 (Pre-) focussing
When you are observing an object, you must have the correct distance to the
objective to achieve a sharp image.
In order to find this distance at the beginning (without other default settings of the
microscope) place the objective with the lowest magnification in the beam path, look
through the right eyepiece with the right eye and turn it slowly using the coarse
adjustment knob.
The simplest way of doing this would be to first raise the nosepiece (using the coarse
adjustment knob) to the top position and then lower it slowly. As soon as an image is
recognisable (no matter how sharp), then you should only adjust the focus using the
fine adjustment knob.
Adjusting the torque of the coarse and fine adjustment knob
Next to the left adjustment wheel for the coarse and fine adjustment knob there is a
ring (
see illustration [1] ) which you can use to alter the torque of these wheels.
Turning it in a clockwise direction reduces the torque and turning it in an anti-
clockwise direction increases it.
On one hand, this function can help to make it easier to adjust the focus and on the
other hand it can prevent the nosepiece from slipping down unintentionally.
Important:
In order to avoid damaging to the focussing system, the left and right adjustment
wheels for the coarse and fine adjustment knob must never be rotated at the same
time in opposite directions.