How to use a Petrographic Microscope

Focusing the Microscope

Every time you use a microscope you must adjust the focus for your eyes. A lot of people protest about eye strain using microscopes, although complaints are usually due to incorrect adjustment. The only exceptions are people with eyes that have non parallel lines of sight. If you include this condition, or if you decline to properly adjust your microscope, use just one eye. Alteration steps, first is alter the width of the eyepieces by using both hands to softly pull or push the eyepiece base plate, or softly rotate the ocular bases to move them beyond apart or closer together. After that, focus the cross hairs for the right eye using the adjustment ring on the right ocular lens. After that, center the view for the right eye using the focusing knobs in the direction of the back of the microscope. These lift up and lesser the stage. And finally, center the view for the left eye using the adjustment ring on the left ocular lens.

Centering the Optics

A lot of diagnostic optical properties of minerals are able to be measured using the polarizing microscope. A few require the stage rotation axis to agree with the rotational symmetry axis of the objectives. It is theoretically simple to center the optics, but it does need practice as well as a steady hand.

Centering the Stage

In terms of centering, the stage is first to put a thin section on the stage and focus using the 10X objective. Only the 10X objective is used to center the stage, as the 10X has no centering adjustment itself. After that, find the stage centering screws. These might be actual screws, Olympus pin wrench screws, or knurled knobs. Then, place a familiar speck of something precisely under the crosshair intersection. Next, rotate the stage awaiting the speck is as far from the intersection as probable. Next, turn the stage centering screws to shift the speck half way back to the crosshair intersection. Then, move the thin section to bring the speck back to the crosshair intersection. And lastly, rotating the stage must leave the speck in the center. If it still rotates away from the crosshair intersection, do again steps 3 to 6 until the speck remnants on the crosshair intersection as the stage is rotated.

Centering the Other Three Objectives

In centering, the other three objectives is first to focus on the thin section using one of the other objectives in turn. Then, fit two pin wrenches into the centering screws for this objective. Then, discover a speck and put it precisely under the crosshair intersection. Then, rotate the stage until the speck is as far from the intersection as likely. Then, turn the pin wrenches on the objective to move the speck half way back to the crosshair intersection. Next is to move the thin section to bring the speck back to the crosshair intersection. Then, rotating the stage must leave the speck in the center. If it still rotates away from the crosshair intersection, do again steps 3 to 6 until the speck remains on the crosshair intersection as the stage is rotated. Last is to do again for the further two objectives.