User Guide

16
Appendix: Collimating
Collimating is the process of aligning a telescope’s optics. Your
Maksutov‑Cassegrain's primary mirror was aligned at the fac‑
tory and should not need adjustment unless the telescope is
handled roughly. This manual contains information on how to
test the collimation of your telescope and instructions for prop‑
er alignment should that be needed.
Star-Testing the Telescope
Before you start adjusting the primary mirror of your telescope,
make certain that it is actually out of collimation by performing
a star test.
Take your telescope out at dusk and let it acclimate to the out‑
side temperature; this usually takes 30‑60 minutes. When it is
dark, point the telescope upwards at a bright star and accu‑
rately center it in the eyepiece’s field of view. Slowly de‑focus
the image with the focusing knob. If the telescope is correctly
collimated, the expanding disk should be a circle (Figure 16).
If the image is unsymmetrical, the scope is out of collimation.
Also, the dark shadow cast by the secondary mirror should
appear in the very center of the out‑of‑focus circle, like the
hole in a donut. If the “hole” appears off‑center, the telescope
is out of collimation.
If you try the star test but the bright star you have selected is
not accurately 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
will need to make slight corrections to the telescope’s position
in order to account for the sky’s apparent motion.
Figure 16. A star test will determine if a telescope’s optics are
properly collimated. An unfocused view of a bright star through the
eyepiece should appear as illustrated on right if optics are perfectly
collimated. If circle is unsymmetrical, as in illustration on left, scope
needs collimation.
Out of collimation Collimated