Optika Italy B-380 Serie Manuel D'instructions page 9

4.0 USING THE MICROSCOPE
Insert the 10x objective rotating the nosepiece.
Rotate the turret of the condenser until you reach the inscription "10".
Loosening the lock screw of the centering telescope, focus on the light ring that you observe.
Rotate the two centering screws in order to move the bright ring until it is perfectly aligned with the
dark ring.
Repeat for the other objectives (only as a verification of the correct centering).
Phase rings will be centered when you see an image like this:
Page 9