This tutorial demonstrates how the condenser is centered in the optical path and the size of the field diaphragm opening is determined when adjusting a microscope for proper K hler illumination.
Operating instructions appear just below the tutorial window.
The default initial state of the microscope is severely out of alignment. This is similar to adjusting the coarse and fine focus on the microscope. On a real microscope, this is usually done using a knurled wheel or lever at the base of the microscope. When comparing this part of the tutorial to a real microscope, consider that this action mimics hand-rotation of the substage condenser elevating knob that moves the condenser up and down with respect to the microscope stage. Slide the X and Y Translation sliders until the closed field diaphragm image is centered in the viewfield.