Figure 5.
The optical tube’s rear cell has three pairs of collimation
screws. The larger knobs are the (often spring-loaded) collimation
knobs while the smaller thumbscrews are the locking screws.
Collimation
knob
Locking
thumbscrew
Out
of
collimation
Collimated
Figure 6.
A star test will determine if the telescope's optics are
properly collimated
.
One-Year Limited Warranty
This Orion product is warranted against defects in materials or work-
manship for a period of one year from the date of purchase. This war-
ranty is for the benefit of the original retail purchaser only. During this
warranty period Orion Telescopes & Binoculars will repair or replace,
at Orion’s option, any warranted instrument that proves to be defec-
tive, provided it is returned postage paid. Proof of purchase (such as
a copy of the original receipt) is required. This warranty is only valid
in the country of purchase.
This warranty does not apply if, in Orion’s judgment, the instrument
has been abused, mishandled, or modified, nor does it apply to nor-
mal wear and tear. This warranty gives you specific legal rights. It is
not intended to remove or restrict your other legal rights under appli-
cable local consumer law; your state or national statutory consumer
rights governing the sale of consumer goods remain fully applicable.
For further warranty information, please visit
www.OrionTelescopes.com/warranty.
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No part of this product instruction or any of its contents may be repro-
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of Orion Telescopes & Binoculars.
A N E M P L O Y E E - O W N E D C O M P A N Y
Figure 4.
Secondary mirror collimation is performed using the three
screws (usually Philips or Allen screws) circled here on the secondary
mirror holder.
Secondary mirror
collimation screws
the other two (
Figure 4
). The goal is to center the primary mirror reflection in
the secondary mirror, as in
Figure 3C
. Don’t worry that the reflection of the
secondary mirror is off-center. You will fix that in the next step. It will take some
trial and error to determine which screws to loosen and tighten to move the
reflection of the primary mirror to the center of the secondary mirror. But be
patient and you’ll get it.
Aligning the Primary Mirror
The final adjustment is made to the primary mirror. It will need adjustment if,
as in
Figure 3C
, the reflection of the primary mirror is centered in the second-
ary mirror, but the small reflection of the secondary mirror is off-center. The
tilt of the primary mirror is adjusted using (usually) three spring-loaded col-
limation knobs and three smaller locking thumbscrews on the back end of the
optical tube (
Figure 5
).
First loosen the three locking thumbscrews a turn or so. Then tighten one of
the collimation knobs about a quarter turn and see if the secondary mirror
reflection has moved closer to the center of the primary (where the center
ring/dot is). If it moved farther away then try loosening the same collimation
knob a bit. Repeat this process on the other two sets of collimation screws, if
necessary, adjusting them one way or the other and seeing if the secondary
mirror reflection moves closer to the center of the primary mirror. It will take a
little trial and error to get a feel for how to tilt the mirror in this way. When the
center hole in your collimating tool is centered as much as possible in the ring/
dot on the primary mirror, your primary mirror is collimated. The view through
the collimation cap should resemble
Figure 3D
.
Finally, very lightly tighten the three locking thumbscrews so that the primary
mirror stays in that adjusted position. A simple star test will tell you whether the
optics are accurately collimated.
Star-Testing the Telescope
When it is dark, point the telescope at a bright star and accurately center
it in the eyepiece’s field of view. Slowly de-focus the image with the focus-
ing knob. You should see a series of diffraction rings surrounding a dark cen-
ter spot, which is the shadow of the secondary mirror. If the diffraction rings
are perfectly circular around the dark spot, telescope is correctly collimated
(
Figure 6
). If the image is unsymmetrical, with rings that are not perfectly circu-
lar and the dark spot is not centered within them, the scope is out of collimation.
Note, however, that if the bright star you have selected is not centered in the
eyepiece, the optics will always appear out of collimation, even though they
may be perfectly aligned. It is critical to keep the star centered, so over time
you may need to make slight corrections to the telescope’s position in order to
account for the sky’s apparent motion.
