Orion NEWTONIAN ASTROGRAPH 9527 - Manual (Page 7)

7
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 9a. If anything is off-center,
proceed with the following collimating procedure.
The Collimation Cap
Your 8" f/4.0 Newtonian Astrograph comes with a “quick col-
limation cap”
(Figure 10). 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 align-
ing the optical components is easier to achieve. The reflec-
tive surface provides a distinct visual reference that is help-
ful in centering the primary and secondary mirror reflections.
Figures 9b through 9e assume that you have the collimation
cap in place.
We strongly recommend the use of a laser collimating tool
such as the Orion LaserMate Deluxe or LaserMate Pro to
aid in collimating the optics. A laser collimator will ensure a
more precise collimation than you can usually achieve with
the included collimation cap. With fast optics like those of the
8" f/4.0 Newtonian Astrograph, getting a very precise colli-
mation is critical for obtaining the sharpest, crispest images,
so a laser collimator is a worthwhile (and small) investment.
However, for the purposes of this instruction, we’ll assume
that you don’t (yet) have a laser collimator, and that you’ll be
using the supplied collimation cap.
The Primary Mirror Center Mark
You’ll notice that the primary mirror of the 8" f/4.0 Newtonian
Astrograph has a tiny ring (sticker) marking its center. This
“center mark” allows you to achieve a very precise collimation
of the mirrors; you don’t have to guess where the exact center
of the mirror is.
Figure 9. 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, as in (e).
Figure 10. The quick collimation cap, which features an inner
reflective surface, helps in centering reflections of the optics in the
focuser during the collimation process.
drawtube
Reflection
of primary
mirror clip
a.
b. c.
d. e.
Reflective surface of
collimation
cap
Center
ring on
primary mirror