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5. Using a Sight tube or Cheshire eyepiece and attach it to the visual back of the
focuser to look at the secondary mirror surface through the pin hole. You can see
the dot on the secondary mirror shown in the Figure 3. Check if the dot moves up
and down in the field of view of the pin hole when you move the secondary mirror
holder to the left and right-hand direction a little.
not be written in the center of the optical axis correctly. Return to the procedure 2.
6. Assuming that cross hairs are put in the field of view shown in the Figure 3, check
which side on the vertical Y axis of the imaginary cross hairs the dot can be seen.
If the dot is just on the line of Y axis, you can proceed to next step. If the dot is
seen on the left-hand side, it means that the secondary mirror is somewhat distant
from the primary mirror. If the dot is seen on the right-hand side, it means that
the secondary mirror is somewhat close to the primary mirror. Please make sure
that you return all the washers to the same place as they are.
7. Next, check which side on the horizontal X axis of the imaginary cross hairs the dot
can be seen. If the dot is just on the line of X axis, you can proceed to next step. If
When it occurs, the dot may
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