The basic parameters of the optical axis:

Material: high quality 45# steel

Outer diameter tolerance: f7-f8

Surface roughness: Ra0.2-0.4

Hard chromium thickness: 0.015-0.025mm

Surface hardness: HV700-1150

Straightness: 0.05-0.10m/m

The 1. adjustable eyepiece focusing cylinder is perpendicular to the main lens tube into the eyepiece cylinder. From the peephole, it can be seen from the peephole to the double cross line (the axis of the focus cylinder of the eyepiece), which is then extended, and will be given to the main mirror wall at a point, marking out this point, measuring its position with the ruler, and referring to the eyepiece. In the position of the focusing barrel in the main lens barrel, we can determine whether the eyepiece focusing tube is perpendicular to the main lens barrel.

2. adjust the pair mirror to remove the peep tube on the axis of the main mirror, install the pair mirror and roughly adjust the direction of the pair mirror, so that the eye can see the image of the main mirror reflected by the mirror in the eye mirror, and the image of the secondary mirror and the cross line after the two reflection should also be seen. From these images we can see the relative position of the secondary mirror and the cross line. If the center of the secondary mirror and the intersection of the cross line coincide, the auxiliary mirror is located on the axis of the main mirror, otherwise the corresponding adjustment is needed.

3. adjust the pair mirror to make it located right below the eye lens

From the direction of the eyepiece focusing tube, the secondary mirror is obviously located below the focusing tube, but after that, the accuracy can not be guaranteed. At this time, the tube is placed in the peephole, and the eye is seen from the peephole. The outer ring is the inner wall of the peephole. The outer outline of the secondary mirror and the outline of the inner wall of the peep tube should satisfy the requirement if it is concentric circle, otherwise the secondary mirror should be adjusted in the axis direction of the main mirror. If the peephole is too small and the light is too dark to see, a white paper can be laid on the wall of the main mirror of the tube. If the peep tube is too thin to see the outer round outline of the pair mirror, the peep pipe can be drawn out or shorten the length.

4. adjust the direction of the secondary mirror, so that the optical axis of the eyepiece can be reflected by the secondary mirror and then point to the center of the primary mirror.

On the basis of the previous step, one side is observed from the peephole with the eye, and one side adjusts the direction of the pair mirror until the outer contour of the image of the main mirror in the pair mirror and the outer round outline of the pair mirror two are concentric.

5. adjust the orientation of the primary mirror to make the optical axis coincide with the optical axis of the eyepiece.

A flashlight is used to illuminate the double cross line of the peep tube, and the eyes are seen from the peephole. The image of the double cross line, the center point of the main mirror and the image of the double cross line through the two reflection can be seen.