page 35
refine the tilt-angle of the diagonal mirror until the entire primary mirror can be seen
centered within the diagonal mirror reflection. When the diagonal mirror is correctly
aligned, it will look like
Fig. 28
(the primary mirror is shown out of alignment).
Primary mirror adjustments
If the diagonal mirror (
1, Fig. 28
) and the reflection of the primary mirror (
2, Fig. 28
)
appear centered within the drawtube (
3, Fig. 28
), but the reflection of your eye and the
reflection of the diagonal mirror (
4, Fig. 28
) appear off-center, you will need to adjust
the primary mirror tilt Phillips-head screws of the primary mirror cell (
3, Fig. 24
). These
primary tilt screws are located behind the primary mirror, at the lower end of the main
tube (
Fig. 22
). To adjust the primary mirror tilt screws, first unscrew several turns the
three hex-head primary mirror cell locking screws (
2, Fig. 24
) that are next to each pri-
mary mirror tilt Phillips-head screw. Then by trial-and-error, turn the primary mirror tilt
Phillips-head screws (
3, Fig. 24
) until you develop a feel for which way to turn each
screw to center the reflection of your eye. Once centered, as in
Fig. 25
, turn the three
hex-head primary mirror cell locking screws (
2, Fig. 24
) to relock the tilt-angle adjust-
ment.
4
5
3
3
1
2
2
2
2
2
1
3
4
1
1
Fig. 27:
Diagonal mirror misalignment.
Fig. 28:
Primary mirror misalignment.
Fig. 25:
Correct collimation.
Fig. 26:
Spider vane misalignment.
