Orion SKYQUEST XX14I - Manual (Page 20)

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3. aligning (Collimating) the
Optical System
Collimating is the process of adjusting the mirrors so they are
aligned with one another. Your telescope’s optics were aligned
at the factory, and should not need much adjustment unless
the telescope was handled roughly in transit. Accurate mir-
ror alignment is important to ensure the peak performance of
your telescope, so it should be checked regularly. Collimating
is a relatively easy process and can be done in daylight or
darkness.
To check collimation, remove the eyepiece and look down the
focuser drawtube. You should see the secondary mirror cen-
tered in the drawtube, as well as the reflection of the primary
mirror centered in the secondary mirror, and the reflection of
the secondary mirror (and your eye) centered in the reflection
of the primary mirror, as in
Figure 35a. If anything is off-cen-
ter, proceed with the following collimating procedure.
The Collimation Cap
Your XX14i comes with a “quick collimation cap”
(Figure 36).
This is a simple cap that fits on the focuser drawtube like a
dust cap, but has a tiny hole in the center and a reflective
inner surface. The collimation cap helps center your eye over
the focuser drawtube so that aligning the optical components
is easier to achieve. The reflective surface provides a distinct
visual reference that is helpful in centering the mirror reflec-
tions.
Figures 35b through 35e assume that you have the
collimation cap in place.
The Primary Mirror Center Mark
You’ll notice that the primary mirror of the XX14i has a small
adhesive ring marking its center. This “center mark” allows
you to achieve a very precise collimation; you don’t have to
guess where the exact center of the mirror is.
NOTE: The center ring sticker need not ever be removed from
the primary mirror. Because it lies directly in the shadow of the
secondary mirror, its presence in no way adversely affects the
optical performance of the telescope or the image quality. That
might seem counterintuitive, but it’s true!
Preparing the Telescope for Collimating
Once you get the hang of collimating, you will be able to do
it quickly even in the dark. For now, it is best to collimate in
daylight, preferably in a brightly lit room and aimed at a light-
colored wall. It is recommended that the telescope tube be
oriented horizontally. This will prevent any parts from the
secondary mirror from falling down onto the primary mirror
Figure 35. Collimating the optics. (a) When the mirrors are properly aligned, the view down the focuser drawtube should look like this.
(b) With the collimation cap in place, if the optics are out of alignment, the view might look something like this. (c) Here, the secondary
mirror is centered under the focuser, but it needs to be adjusted (tilted) so that the entire primary mirror is visible. (d) The secondary mirror is
correctly aligned, but the primary mirror still needs adjustment. When the primary mirror is correctly aligned, the center “dot” of the collimation
cap will be centered in the ring on the primary mirror, as in (e) .
drawtube
Reflection
of primary
mirror clip
Primary mirror
center mark
Reflective surface
of collimation
cap
a.
b. c.
d. e.
Figure 36. The included “quick collimation cap” has a hole in the
center and a reflective inner surface.