The fiducial is an adjustment aid. It is configured as follows.

When the fiducial is called, up an entry window appears in which the

size and the number of blades on the fiducial have to be entered.

The size is always entered together with a decimal separator, a point

or comma. Next a blank space has to be entered and then the number

of the "segments" (a whole number).

The example here is for a diameter of 2.3 mm and 5 "segments": 

The fiducial can be positioned by opening a hair cross or by the 

cursor control. Not all the hair crosses are available for the fiducial!

       

 

This is how the fiducial appears after clicking on OK.

The simple hair cross displayed can be used to shift the fiducial.

Once created a fiducial can be saved together with its size

and position for later use, under Save settings.