Orion SPACEPROBE 130ST EQ - Manual (Page 6)

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horizontal position.
5. With one hand on the telescope optical tube, loosen the
Dec. lock knob. The telescope should now be able to
rotate freely about the Dec. axis. Loosen the tube ring
clamps a few turns, until you can slide the telescope tube
forward and back inside the rings (this can be aided by
using a slight twisting motion on the optical tube while
you push or pull on it) (Figure 4c).
6. Position the telescope so it remains horizontal when you
carefully let go with both hands. This is the balance point
(Figure 4d). Before clamping the rings tight again, rotate
the telescope so the eyepiece is at a convenient angle for
viewing. When you are actually observing with the tele-
scope, you can adjust the eyepiece position by loosening
the tube rings and rotating the optical tube.
7. Retighten the tube ring clamps.
The telescope is now balanced on both axes. Now when you
loosen the lock knob on one or both axes and manually point
the telescope, it should move without resistance and should
not drift from where you point it.
Focusing the telescope
With the 25mm Sirius Plössl eyepiece in the focuser, move
the telescope so the front (open) end is pointing in the gen-
eral direction of an object at least 1/4-mile away. Now, with
your fingers, slowly rotate one of the focusing 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’ve hit the
exact focus point.
If you have trouble focusing, rotate the focus knob so the
drawtube is in as far as it will go. Now look through the eye-
piece while slowly rotating the focus knob in the opposite
direction. You should soon see the point at which focus is
reached.
Do You Wear 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 eas-
ily observe with your glasses off by just refocusing the tele-
scope the needed amount.
Aligning the Finder Scope
The finder scope (Figure 3a) must be aligned accurately with
the telescope for proper use. To align it, aim the main tele-
scope in the general direction of an object at least 1/4-mile
away, such as the top of a telephone pole, a chimney, etc. Do
this by first loosening the R.A. and Dec. lock knobs. Position
the telescope so the object appears in the eyepiece’s field of
view and then retighten the R.A. and Dec. lock knobs. Use
the slow-motion control cables to center the object in the
eyepiece.
Now, look in the finder scope. Is the object visible? Ideally,
it will be somewhere in the finder’s field of view. If it is not,
some coarse adjustments of the two black nylon finder scope
alignment thumb screws will be needed to get the finder
scope roughly parallel to the main tube.
Note: The image in both the finder scope and the main
telescope will appear upside-down (rotated 180°). This is
normal for finder scopes and reflector telescopes (see
Figure 5).
By loosening or tightening the alignment thumb screws, you
change the line of sight of the finder scope. Continue making
adjustments to the alignment thumb screws until the image in
both the finder scope and the telescope’s eyepiece is exactly
centered. Check the alignment by moving the telescope to
another object and fixing the finder scope’s crosshairs on
the exact point you want to look at. Then look through the
telescope’s eyepiece to see if that point is centered in the
field of view. If it is, the job is done. If not, make the neces-
sary adjustments until the two images match up.
The finder scope alignment needs to be checked before
every observing session. This can easily be done at night,
before viewing through the telescope. Choose any bright
star or planet, center the object in the telescope eyepiece,
and then adjust the finder scope’s alignment screws until
the star or planet is also centered on the finder’s crosshairs.
The finder scope is an invaluable tool for locating objects in
the night sky; its usage for this purpose will be discussed
later, in detail.
When transporting the telescope, we recommend removing
the finder scope and bracket from the tube. This is done by
simply loosening the thumbscrew on the dovetail slot.
Store the finder scope and bracket in an appropriate eye-
piece/accessory case.
Naked-eye view
View through finder scope and telescope
Figure 5. The view through a standard finder scope and reflector
telescope is upside down. This is true for the SpaceProbe 130ST
and its finder scope as well.