The general sight structure is: eyepiece, plate (or sub-line) variable multiplied by the tube (controlled by the external variable double loop); when the magnification of the zoom tube after the end of the board changes and differences, so the size of the object With the wire size changes.
The pre-differentiation of the target plate structure is: the eyepiece variable is multiplied by the differentiation of the tube (controlled by the external variable double loop) - the plate (or differentiation); when the magnification changes, due to the change in the change in the front end of the tube Is a prerequisite, so objects and crossovers will also increase or decrease).
The comparison of these two structures can be concluded:
(1)Causing differentiation, adjusted for the size of the adjustment rate, followed by small changes in small, so that no change in the error, while the general posts are not.
(2)Leading to differentiation mainly due to the differentiation of the glass plate, since the preceding target is in the middle of the lens and the middle position of the objective lens, which is the center of the mirror where the wire is almost impossible to position the wire.