4
Primary Mirror Cell The mechanical holder for the primary
mirror, with alignment adjusting bolts that allow exact posi-
tioning (tilt) of the primary mirror.
Rack-and-Pinion Focuser A type of focusing device that
employs a grooved “rack” and a meshing pinion gear to move
the eyepiece-holding drawtube in and out, thereby allowing
adjustment of the image focus.
Secondary Mirror The small, elliptical-shaped, flat optical
mirror, located inside the optical tube beneath the focuser,
that diverts light sideways into the focuser tube.
Secondary Mirror Holder The mechanical holder for the sec-
ondary mirror; usually a single stalk or a multi-vane “spider.”
2. Parts List
1
Optical tube assembly with altazimuth yoke mount and
altitude micro-motion control bar attached
1
Altitude lock knob
1
5x24 achromatic finder scope with mounting bracket and
bolts
1
20mm (35x) Kellner eyepiece (.965")
1
Optical tube dust cap
3
Adjustable wood tripod legs; 3 leg bolts with large wing
nuts and washers
1
Accessory tray; 3 small wing nuts and washers
3. Getting Started
Unpacking Your Telescope
Compare the labeled diagram of the telescope and acces-
sories to the contents in the box you have just opened. Make
sure all the parts are present. Keep the original shipping box
in case you should need to return the telescope to Orion for
warranty repair service. The box also makes a very good con-
tainer for storing the telescope when it is not in use.
Assembly
This telescope comes largely preassembled. All that is
needed is to attach the tripod legs, accessory tray, and
finder scope.
The tripod legs attach to the aluminum base of the altazimuth
mount. Attach a leg to each of the three flanges by aligning
the hole in the leg with the holes in the flange and inserting
the long bolt through the holes. Place a washer over the
threaded end of the bolt and then thread on a large wing nut.
Note that the hinged metal plate on each tripod leg should
face inward, not outward, when the legs are properly orient-
ed. Do not tighten the wing nuts completely just yet. Next,
spread the legs apart and attach the accessory tray to the
hinged plates on the legs with the small screws, wing nuts,
and washers provided. Spread the legs apart as far as they
will go and tighten the wing nuts. Now, return to the joints
where the legs attach to the altazimuth mount and tighten the
large wing nuts.
Screw on the altitude lock bolt. When it’s tight, it prevents the
altitude control bar from moving.
The finder scope will be mounted on the front end of the opti-
cal tube next to the focuser. Before removing the two nuts
from the mounting screws, place your hand inside the tele-
scope tube and hold the small bar on which the screws are
mounted.
If you do not do this, the piece could drop off and
damage the primary or secondary mirror. With the optical tube
in a horizontal position (parallel to the ground), remove the two
nuts and install the finder scope, then replace the nuts.
Finally, place the eyepiece into the focuser drawtube and secure
it in place with the knurled setscrew. The telescope is now nearly
ready for “first light.” The one final adjustment needed will be to
align the finder scope to the main telescope’s optical system.
Aligning the Finder Scope
Having a finder scope makes it easy to locate objects in the
night sky. It provides low power and a wide field of view with
which to home in on objects of interest. When the finder
scope is properly aligned with the main telescope, an object
that is centered on the crosshairs of the finder scope will
appear right in the center of your telescope’s eyepiece.
The finder scope and the telescope should be aligned to point
to exactly the same spot in the sky. Alignment is easiest to do
in daylight hours, before your observing session. First, make
sure the eyepiece has been inserted in the focuser. Choose
a tree, telephone pole, street sign—anything that is far off in
the distance, at least 200 yards away. Put that image in the
center of the field of your telescope’s eyepiece. Now, where
is it in your finder scope’s field of view? Hopefully, the image
will be visible in the finder scope and some simple adjust-
ments of the three alignment screws of the finder scope
mounting bracket will put the image dead center at the inter-
section of the crosshairs. (Note that the image will appear
upside down in the finder scope. This is normal.) By loosen-
ing one alignment screw and tightening another, you can
change the line of sight of the finder scope. Continue making
adjustments to the alignment screws until the image in both
the finder scope and the telescope’s eyepiece is exactly cen-
tered. Check the alignment by moving the telescope to
another object and fixing the finder scope crosshairs on the
exact point you want to look at. Then look through the tele-
scope’s eyepiece to see if that point is in the middle of the
telescope’s field of view. If it is, the job is done. If not, make
the necessary adjustments to the finder scope alignment until
the two images match up.
Finder scopes often come out of alignment during trans-
portation from site to site, so check the alignment before each
observing session. One way to help minimize any misalign-
ment is to keep the bolts that attach the finder scope bracket
to the main telescope tube fairly tight.
4. Using Your Telescope
Transporting the Telescope
The SpaceProbe 3" is a highly portable telescope—easy to
take wherever you want to do your observing. You’ll be
