Meade Instruments Polaris Series - Manual (Page 23)

grasping the secondary holder with your
hand, tilt the secondary mirror holder until you
see the primary mirror become as centered
in the reflection of the diagonal mirror as
possible. Once you are at the best position,
thread in the 3 Phillips-head secondary mirror
collimation screws to lock the holder in place.
Then, if necessary, make adjustments to
these 3 Phillips-head screws to refine the tilt-
angle of the secondary mirror until the entire
primary mirror can be seen centered within
the secondary mirror reflection. When the
secondary mirror is correctly aligned, it will
look like Fig. 16 (Note: The primary mirror is
shown out of alignment).
C. PRIMARY MIRROR ADJUSTMENTS
If the secondary mirror (1, Fig. 16) and the
reflection of the primary mirror (2, Fig. 16)
appear centered within the draw tube (3, Fig.
16), but the reflection of your eye and the
reflection of the secondary mirror (4, Fig. 16)
appear off center, you will need to adjust the
primary mirror tilt screws of the primary mirror
cell (2, Fig. 13). These primary tilt screws
are located behind the primary mirror, at the
lower end of the main tube.
To adjust the primary mirror tilt screws (2, Fig
13), first turn by several turns, the primary
mirror cell lock knobs (3, Fig. 13) that are next
to each primary mirror tilt screw. The three
primary mirror cell locking screws are Phillips
head screws on all Polaris models.
Then by trial-and-error, turn the primary mirror
tilt knobs (2, Fig. 13) until you develop a feel
for which way to turn each knob to center the
reflection of your eye. Once centered, as in
Fig. 14, turn the 3 primary mirror cell locking
screws (3, Fig. 13) to re-lock the tilt-angle
adjustment.
NOTE: Some models have large thumb knobs
for the primary mirror cell tilt knobs(2, Fig 13).
Other models have Phillips head screws as
the primary mirror cell tilt screws. On these
models, the primary mirror cell tilt screws (2,
Fig 13) are the screws that have the screw
heads touching the rear cell.
D. STAR TESTING THE COLLIMATION
With the collimation performed, you will want
to test the accuracy of the alignment on a
star. Use the 25mm eyepiece and point the
telescope at a moderately bright (second or
third magnitude) star, then center the
star image in the telescope’s field-of-
view. With the star centered follow the
method below:
• Bring the star image slowly out of focus
until one or more rings are visible around the
central disc. If the collimation was performed
correctly, the central star disk and rings will
be concentric circles, with a dark spot dead
center within the out-of-focus star disk (this
is the shadow of the secondary mirror), as
shown in Fig. 17C. (An improperly aligned
telescope will reveal elongated circles (Fig.
17A), with an off-center dark shadow.)
•If the out-of-focus star disk appears
elongated (Fig. 17A), you will need to adjust
the primary mirror adjusting tilt screws of the
primary mirror cell (3, Fig. 13)
•To adjust the primary mirror tilt screws (3,
Fig. 13), first unscrew several turns the 3
hex-head primary mirror cell locking screws
(2, Fig. 13), to allow free turning movement
of the tilt knobs.
•Using the flexible cable controls move the
telescope until the star image is at the edge
of the field-of-view in the eyepiece, as in Fig.
21
Looking at or near the Sun will cause irreversable damage to your eye. Do not point this telescope at or near the Sun. Do not look through the telescope as it is moving.