How To Center Microscope Stage

How To Center Microscope Stage.

How To Center Microscope Stage.

How To Centre the Microscope Stage

. If the microscope has a revolving stage, turn this to see whether the object or portion of it lying in the center of the field, remains in the optical axis. It was true when the instrument was shipped, but may have changed during transportation. If not centered, loosen the screwholding it to the arm by means of the steel pin, just sufficiently that by the exertion of a little pressure it can be moved. After having observed first which portion of the object remains stationary during its revolution (this evidently is its center) move the stage so that this point will be in the center of the field, and then tighten the screw. If the point lies outside of the limits of the field, its direction can be noted and the stage moved accordingly. Where centering screws are provided in the instrument, this is a simple matter.

If the coarse adjustment does not prove sensitive enough to focus easily, adjust by the fine adjustment by taking the head of the micrometer screw between the thumb and first finger and move toward the right or left as may be necessary.

It may here be said in passing that the rack and pinion should be so well fitted that they should permit the adjustment of low power objectives with the greatest ease, and should work without the slightest lost motion with a or inch objective. This point is the criterion of workmanship in an instrument, and if it is found to have the least back-lash, or is not perfectly smooth, it may safely be assumed that the instrument is of inferior workmanship.

If the fine adjustment does not act, the screw has either come to its stop, or has "run out," and must be brought into action again ; the range of movement in almost all fine adjustments is quite short and constant care must be taken to keep it at about a medium point. If the object is found not to give a full view or is not in the center of the field, it must be moved on the stage, but it must be remembered that a movement in one direction causes an apparent opposite movement in the field. At first this movement will be in jerks, but after a little practice the necessary sensitiveness of touch is acquired to give it more steadiness.