OPERATION
ZEISS
Illumination and contrast methods in transmitted light …
Axioscope 5/7/Vario
108
430035-7344-001
03/2018
(2) Setting the microscope for conoscopy using the Bertrand system module
•
Set the microscope as for transmitted light brightfield microscopy using the KÖHLER method(see also
section 4.2.1).
•
Put the specimen onto the stage and focus on it.
•
Move the polarizer into the light path.
•
If you do not use the Pol binocular photo tube, carry out the next two steps:
−
Align the crossline micrometer 14:140 or the eyepiece reticle to the vibration direction of the
polarizer using the Pol adjustment tool. Please refer to section 4.2.6.2.
NOTE
If you do not use the Pol binocular photo tube for your work, you must realign the
crossline micrometer or eyepiece reticle after changing the inter-pupillary distance on
the binocular tube.
−
Remove the Pol adjustment tool.
•
Put the specimen onto the stage and focus on it.
In the case of uniaxial crystals, the most favorable orientation for conoscopic viewing is obtained with
those specimen features (e.g. of a thin section) that in orthoscopic viewing change the brightness as little
as possible upon rotating the stage. In this case, the direction of viewing and the optical axis are
±
parallel. The same refers also to biaxial crystals, if they are viewed along or approximately in the
direction of one of the two optical axes.
•
Move a selected crystal to the center of the reticle.
•
Swivel the front lens on the condenser into the light path.
•
Swivel in the N-Achroplan 50x/0.8 Pol objective or the EC EPN 40x/0.9 Pol objective and focus with the
focusing drive.
•
Close the luminous-field diaphragm as much as is necessary to prevent the axial figure from being
superimposed by the axial figures of adjacent crystals. The smallest crystal extension that can be
masked out is 4 µm.
•
Swivel in the Pol Bertrand system module on the reflector turret. Afterwards, the axial figure appears
in the field of view.