Orion SKYQUEST XT10 CLASSIC - Manual (Page 10)

alignment is important to ensure the peak performance of your
telescope, so it should be checked regularly. Collimation is rela-
tively easy to do and can be done in daylight.
To check collimation, remove the eyepiece and look down the
focuser drawtube. You should see the secondary mirror centered
in the drawtube, as well as the reflection of the primary mirror cen-
tered in the secondary mirror, and the reflection of the secondary
mirror (and your eye) centered in the reflection of the primary mir-
ror, as in Figure 13a. If anything is off-center, as in Figure 13b,
proceed with the following collimation procedure.
the collimation cap and Mirror center Mark
Your SkyQuest XT comes with a collimation cap. This is a sim-
ple cap that fits on the focuser drawtube like a dust cap, but has
a hole in the center and a silver bottom. This helps center your
eye so that collimation is easy to perform. Figures 13a through
13e assume you have the collimation cap in place.
In addition to providing the collimation cap, you’ll notice a tiny
ring (sticker) in the exact center of the primary mirror. This
“center mark” allows you to achieve a very precise collima-
tion of the primary mirror; you don’t have to guess where the
center of the mirror is. You simply adjust the mirror position
(described below) until the reflection of the hole in the collima-
tion cap is centered inside the ring. This center mark is also
required for best results with other collimating devices, such
as Orion’s LaserMate Laser Collimator, obviating the need to
remove the primary mirror and mark it yourself.
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!
aligning the secondary Mirror
With the collimation cap in place, look through the hole in the
cap at the secondary (diagonal) mirror. Ignore the reflections
for the time being. The secondary mirror itself should be cen-
tered in the focuser drawtube, in the direction parallel to the
length of the telescope. If it isn’t, as in Figure 13b, it must be
adjusted. This adjustment will rarely, if ever, need to be done. It
helps to adjust the secondary mirror in a brightly lit room with
the telescope pointed toward a bright surface, such as white
paper or wall. Placing a piece of white paper in the telescope
tube opposite the focuser (i.e., on the other side of the sec-
ondary mirror) will also be helpful in collimating the secondary
mirror. Using a 2mm hex key, loosen the three small alignment
set screws in the center hub of the 4-vaned spider several
turns. Now hold the mirror holder stationary (be careful not
to touch the surface of the mirrors), while turning the center
screw with a Phillips head screwdriver (see Figure 14). Turning
the screw clockwise will move the secondary mirror toward
the front opening of the optical tube, while turning the screw
counter-clockwise will move the secondary mirror toward the
primary mirror.
Note: When making these adjustments, be careful not to
stress the spider vanes or they may bend.
When the secondary mirror is centered in the focuser draw-
tube, rotate the secondary mirror holder until the reflection of
the primary mirror is as centered in the secondary mirror as
10
drawtube
Reflection
of primary
mirror clip
a. d.
c.
e.
b.
Figure 13. 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 “dot” will be centered, as in (e).