Orion SKYQUEST XX12 - Manual (Page 20)

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Focusing the telescope
The XX12 comes standard with a 2" dual-speed Crayford fo-
cuser. The large 2" format focuser allows use of 2" or 1.25"
eyepieces and the Crayford design prevents imaging shifting
while focusing. The focuser has coarse focus knobs and a fine
focus knob for most precise focusing.
With the 35mm Deep View eyepiece in the focuser and
secured with the thumb screws, move the telescope so the
front end is pointing in the general direction of an object at
least 1/4-mile away. Now, with your fingers, slowly rotate one
of the coarse focus knobs until the object comes into sharp
focus. Go a little bit beyond sharp focus until the image just
starts to blur again, then reverse the rotation of the knob, just
to make sure you’re close to the focus point.
Now, use the fine focus knob to achieve precise focus. Eleven
turns of the fine focus knob turns the coarse focus knobs only
once, so it offers much finer adjustment than is possible with
just the coarse focus knobs alone. You’ll find this is a great
convenience, especially when attempting to focus at high
magnifications.
If you have trouble focusing, rotate the coarse focusing knob
so the drawtube is inward as far as it will go. Now look through
the eyepiece while slowly rotating the focusing knob in the
opposite direction. You should soon see the point at which
focus is reached.
The thumb screw on the bottom of the body of the focuser
(Figure 29) will lock the focuser drawtube in place once the
telescope is properly focused. Before focusing, remember to
first loosen this thumb screw.
If you find the drawtube tension when focusing is either too
tight (i.e. focus knob is difficult to turn) or too loose (i.e. draw-
tube moves by itself under the weight of the eyepiece), you
can adjust it by tightening or loosening the drawtube tension-
ing set screw on the focuser, which is located just below the
focus lock thumb screw (Figure 29). Adjust this set screw with
the included 2.5mm hex key. Do not loosen the set screw too
much as there must be some tension to keep the drawtube
secure within the focuser. The other set screw below the
drawtube tensioning set screw does not affect drawtube ten-
sion and should not be adjusted.
Viewing with Eyeglasses
If you wear eyeglasses, you may be able to keep them on while
you observe, if your eyepieces have enough eye relief to allow
you to see the whole field of view. You can try this by looking
through the eyepiece first with your glasses on and then with
them off, and see if the glasses restrict the view to only a
portion of the full field. If they do, you can easily observe with
your glasses off by just refocusing the telescope as needed.
If you suffer from severe astigmatism, however, you may find
images noticeably sharper with your glasses on.
aligning the Finder scope
SkyQuest IntelliScope Dobsonians come with a high-quality,
large-aperture 9x50 achromatic crosshair finder scope as
standard equipment (Figure 39). This greatly aids in find-
ing objects to view in the night sky. The finder scope must
be accurately aligned with the telescope for proper use. The
finder scope uses a spring-loaded bracket which makes align-
ment very easy. As you turn either of the thumb screws, the
spring in the bracket’s tensioner moves in-and-out to keep the
finder scope secure in its bracket.
To align the finder scope, first aim the main telescope in the
general direction of an object at least 1/4-mile away - the top
of a telephone pole, a chimney, etc. Position that object in the
center of the telescope’s eyepiece.
Note: The image in the finder scope and the telescope will
appear rotated 180°. This is normal for finder scopes and
reflector telescopes (Figure 40).
Now look through the finder scope. Ideally, the object should
be within the field of view. If not, then coarse adjustments to
the bracket’s alignment thumb screws will be needed. Once
the image is in the finder scope’s field of view, you will now
use the bracket’s alignment thumb screws to center the object
on the intersection of the crosshairs. By loosening or tighten-
Finder scope
Finder scope bracket
Nylon alignment
thumbscrews
Focus
lock ring
Figure 39. The 9x50 finder scope.
Tensioner
Naked-eye view
View through finder scope and telescope
Figure 40. The view through a straight finder scope and reflector
telescope is rotated 180°. This is true for the XX12 and its finder
scope as well.