Orion XT4.5 - Manual (Page 4)

4
2. Assembly
Now that you have unpacked the boxes and familiarized
yourself with all the parts in front of you, it's time to begin
assembly. The optics of the telescope are already installed in
the tube, so most of the required assembly concerns the
Dobsonian base.
Assembly of the Dobsonian base
Refer to Figure 2 during base assembly. The base need only
be assembled once. The assembly process takes about 30
minutes and requires a Phillips screwdriver, and an
adjustable crescent wrench. When tightening screws, tighten
them until firm, but be careful not to strip the holes by over-
tightening. Children under the age of 12 should work with an
adult.
1. Screw the plastic feet into the underside of the ground
baseplate (A) using the self-tapping wood screws provided,
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 four of the base assembly screws in the predrilled
holes. The side panels should be oriented so the SkyQuest
labels are facing outward. 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 assembly
screws in the predrilled holes. Tighten all six screws.
4. Tighten the four side screws installed earlier. Press a trim
cap onto the heads of each of these screws.
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 base-
plate (A) so the nut’s flanged top is on the same side of the
baseplate as the Teflon pads. Thread the large hex-head
bolt (G) with a 3/8" washer (F) attached up through the
ground baseplate and through the T-nut until it is tight.
7. Now position the top baseplate (D) (with side panels
attached) over the ground baseplate and lower it so the bolt
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 bolt’s shaft. You might need to hold the
bolt's head in place with another crescent wrench or pliers.
Tighten the lock nut with the 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 coming apart when moving the tel-
escope. Over-tightening the lock nut (I) will make the mount
difficult to rotate in the azimuthal (horizontal) direction.
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 surface 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 3. Press firmly so the adhesive holds the bumper
securely in place.
Installing the Eyepiece Rack
The aluminum eyepiece rack holds three 1.25" eyepieces in
a convenient place on the base, within easy reach while
you're observing. A 1.25" barlow can also be held in the rack.
Figure 2. Exploded view of the Dobsonian base.
C
C
B
D
F
I
H
L
E
G
A
K
Figure 3. Position the rubber bumper “stop” over the index mark on
the inside surface of the front brace.