Orion 9966 - Manual (Page 6)

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tighten them until firm, but be careful not to strip the holes
by over-tightening. If you use an electric screwdriver, do final
tightening with a standard screwdriver to avoid stripping.
1. Screw the plastic feet into the underside of the ground
baseplate (A) using the self-tapping wood screws provid-
ed, with a Phillips screwdriver. Insert the screws through
the feet and thread them into the predrilled starter holes.
2. Loosely attach the front brace (B) to the two side panels
(C) with six of the base assembly screws in the predrilled
holes. Use the 4mm hex key to tighten the screws. The
side panels should be oriented so the SkyQuest labels are
facing outward. The front brace should be oriented so the
index mark is facing inwards. Do not completely tighten
the screws yet.
3. Attach the two sides (C) with the front brace attached to
the top baseplate (D) with the remaining six base assem-
bly screws in the predrilled holes. Tighten all six screws.
4. Tighten the six side screws installed earlier.
5. Insert the white nylon bushing (E) into the hole in the cen-
ter of the top baseplate (D). Tap the nylon bushing in so it
goes all the way into the top baseplate. The nylon bushing
should be flush with the top surface of the top baseplate.
6. Insert the T-nut (K) into the center hole of the ground
baseplate (A) so the nut’s flanged top is on the same
side of the baseplate as the Teflon pads. Thread the large
hex-head screw (G) with a 3/8" washer (F) attached up
through the ground baseplate and through the T-nut until it
is tight. Now position the top baseplate (D) (with side pan-
els attached) over the ground baseplate and lower it so the
screw goes through the nylon spacer in the center hole of
the top baseplate. Now thread the remaining 3/8" washer
(H) and lock nut (I) onto the screw’s shaft. You might need
to hold the screw’s head in place with another crescent
wrench or pliers. Tighten the lock nut with a wrench just
enough to allow a slight separation of the top and bottom
baseplates when the mount is lifted. The purpose of the
lock nut is merely to keep the two baseplates from com-
ing apart when moving the telescope. Overtightening the
lock nut (I) will make the mount difficult to rotate in the
azimuthal (horizontal) direction.
7. Attach the handle (J) to the front brace (B) with the two
black socket-head cap screws. Insert the screws through
the handle and into the predrilled holes. Place the 5/16"
washers and 5/16" nuts on the protruding ends of the
screws. Tighten the nuts with a crescent wrench while
holding the screws stationary with the 6mm hex key.
8. The rubber bumper (L) provides a convenient “stop” for
the telescope’s altitude motion; it prevents the telescope
mirror cell from being knocked against the hard surface
of the base’s front brace. At the bottom of the interior sur-
face of the front brace, you will notice a small index mark
engraved. Remove the backing from the rubber bumper
and position the bumper over the index mark, as shown in
Figure 10. Press firmly so the adhesive holds the bumper
securely in place.
Installing the Eyepiece Rack
The aluminum eyepiece rack is a standard accessory on
SkyQuest XT12 Dobsonians. It holds three 1.25" eyepieces
and one 2" eyepiece in a convenient place on the base, within
easy reach while you’re observing. A 1.25" barlow lens also
can be held in the rack. About halfway down the left side
Figure 10. Position the rubber bumper “stop” over the index mark
on the inside surface of the front brace.
Figure 11. Using the two supplied screws, install the aluminum
eyepiece rack in the predrilled holes about halfway down the left side
panel of the base.
Figure 12. Set the optical
tube on the “cradle” of the
base so that the altitude side
bearings on the tube rest on
the white plastic “pads.”