9
Adjusting the main mirror
Once the secondary appears round and the mark on the main mirror is centered, check the collimation of the
main mirror. If the reflection of your eye and the reflection of the secondary mirror on the main mirror are not
concentric, insert the collimating tool into one of the collimation screws that are located on each side of the main
mirror, Figure 9.1. When you turn the collimation tool you will notice that the hexagonal head of the tool will lock
into the hexagonal head of the collimation screw. Now you can adjust the main mirror by turning the collimation
tool, Figure 9.2. Adjust the screws until the eye and the reflection of the secondary are centered in the main mirror.
Practice this until you get a feel of what a turn of one of the collimation screws is doing.
Collimation
Figure 9.1
Figure 9.2
Collimation Screw
Collimation Tool