Orion XT10 CLASSIC, XT8 CLASSIC User Manual

INSTRUCTION MANUAL

Orion® SkyQuest

XT6 Classic, XT8 Classic

& XT10 Classic

Dobsonian Reflecting Telescopes

Providing Exceptional Consumer Optical Products Since 1975

OrionTelescopes.com

Customer Support [phone]
E-mail: [e-mail]

Corporate Offices [phone]

89 Hangar Way, Watsonville, CA 95076

IN 165 Rev. D 05/08

Secondary mirror with
4-vane spider (not shown)

EZ Finder II

Eyepiece

Focus knob

Optical tube

Altitude side bearing

Right side panel

Front brace

Handle

Eyepiece Rack
(optional)

Top baseplate

Ground baseplate

Figure 1.

CorrecTension Friction

Optimization System

Pull loop

Left side panel

The SkyQuest XT Dobsonian (XT6 pictured)

2

Welcome to an exciting new world of adventure! Your SkyQuest Dobsonian is a high-quality optical instrument designed to

bring you dazzling views of the outer reaches of our universe. Easy enough for kids to use, and portable enough for any­one to carry, the SkyQuest will provide fun and entertainment for the entire family. Whether you are brand-new to amateur
astronomy or a seasoned stargazer, get ready for many evenings of enjoyment and fascination. Before venturing into
the night with your new telescope, we recommend that you read through this instruction manual. Not only does it provide
accurate directions for assembly and use, but it also serves as a guide for your first explorations in the sky.

Table of Contents

1. Unpacking.............................3

2. Assembly .............................4

3. Using Your Telescope ....................7

4. Collimation (Aligning the Mirrors) ..........10

5. Astronomical Observing .................12

6. Care and Maintenance ..................16

7. Specifications .........................17

1. Unpacking

The telescope will arrive in two boxes, one containing the
optical tube assembly and accessories, the other containing
the unassembled Dobsonian base. Be careful unpacking the
boxes. We recommend keeping the original shipping contain­ers. In the event that the telescope needs to be shipped to
another location, or returned to Orion for warranty repair, hav­ing the proper shipping containers will help ensure that your
telescope will survive the journey intact.

Make sure all the parts in the Parts List below are present. Be
sure to check boxes carefully, as some parts are small. If any­thing appears to be missing or broken, immediately call Orion
Customer Support (800-676-1343) for assistance.

WARNING: Never look directly at the Sun

through your telescope or its finder scope—
even for an instant—without a professionally
made solar filter that completely covers the front
of the instrument, or permanent eye damage
could result. Young children should use this
telescope only with adult supervision.

Parts List

Box #1: Optical Tube Assembly and Accessories

Qty. Description

1 Optical tube assembly

1 Dust cover

1 25mm Sirius Plössl eyepiece, 1.25" barrel diameter

1 EZ Finder II (with bracket)

1 Collimation cap

2 Spring coils

2 Pull loops

4 Nylon spacers (black)

2 1/4" washers (black)

2 Phillips-head screws (black, length 1-3/4")

2 Screws with round knob attached

Box #2: Dobsonian Base

Qty. Description

1 Left panel

1 Right panel

1 Front brace

1 Top baseplate

1 Ground baseplate

12 Base assembly screws (length 2")

1 Hex key (size 4mm)

3 Plastic feet

3 Feet attachment wood screws (length 1")

1 Self-adhesive rubber bumper

1 Large hex-head bolt (length 3")

2 3/8" washers

1 3/8" lock nut

1 Nylon spacer (white)

1 T-nut

1 Handle

2 Socket-head cap screws, 5/16" (black)

2 5/16" washers (black)

2 5/16" nuts (black)

1 Hex key (6mm)

3

F

G

C

C

B

D

J

A

I

H

K

L

E

Figure 3. 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,” and
the finder is facing away from
the front brace (Part B).

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 six side panel screws installed earlier.

5. Insert the white nylon bushing (E) into the hole in the cen­ter of the top baseplate (D). Tap the nylon bushing in so it

Figure 2. Exploded view of the SkyQuest XT Dobsonian base.

goes all the way into the top baseplate. The nylon bushing
should be flush with the top surface of the top baseplate.

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, unless you disassemble it for long-term
storage. The assembly process takes about 30 minutes and
requires a Phillips screwdriver, an adjustable crescent wrench,
and the provided hex keys.

Note: When tightening the base assembly screws, tight­en them until firm, but be careful not to strip the holes
by over-tightening. If you use an electric screwdriver, do
the final tightening with a standard screwdriver to avoid

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
bolt (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 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 bolts shaft. You might need to hold the
bolts 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 telescope.

Note: Overtightening the lock nut (I) will make the mount
difficult to rotate in the azimuthal (horizontal) direction.

stripping.

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 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 label is facing
outward. Do not completely tighten the screws yet.

7. Attach the handle (J) to the front brace (B) with the two
black socket-head 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
bolts stationary with the 6mm hex key.

8. Lift the optical tube and set the altitude bearings on either
side of the tube in the “cradle” of the base (Figure 3). The
unique flange design of the altitude bearing allows for auto­matic left-to-right centering of the optical tube in the cradle.

4

a. b.

Figure 4. Position the tube on the mount pointed vertical. Place

the rubber bumper “stop” where the mirror cell contacts the front
base to cushion the impact.

Once in the cradle, the tube should pivot freely up and
down with gentle hand pressure. Note that the tube will
not yet be properly balanced, since the eyepiece and EZ
Finder II are not in place, and the CorrecTension system
has not been installed.

9. 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. Remove the backing from the rubber
bumper and position the bumper so it is positioned in the
spot where the optical tube (mirror cell) contacts the front
base as shown in Figure 4a and 4b. Press firmly so the
adhesive holds the bumper securely in place.

Installing the Optional Eyepiece Rack

The aluminum eyepiece rack is an optional accessory for
SkyQuest Dobsonians. On the XT6 it holds three 1.25" eye­pieces in a convenient place on the base; on the XT8 and
XT10 it holds three 1.25" eyepieces and one 2" eyepiece.
These eyepieces will be within easy reach while you’re
observing. About halfway down the left side panel of the base
you will notice two predrilled starter holes, about 6" apart.
Take the black wood screws and thread them into the starter
holes with a Phillips screwdriver. Then you can “keyhole” the
eyepiece rack onto the wood screws and continue tightening
the screws (Figure 5). If you want to be able to remove the
rack, do not tighten the screws too tightly. Be certain that the
screws are loose enough that you can lift the rack and remove
it from the screws through the larger part of the keyhole. If
you want to have the rack permanently attached, thread the
screws tightly.

Installing the EZ Finder II

Using the included dovetail mounting bracket, the EZ Finder
II will slip neatly into the dovetail base preinstalled on your
SkyQuest optical tube. To attach the dovetail mounting bracket
to the EZ Finder II, loosen the two thumbscrews on the bottom
rail of the EZ Finder II. Slide the EZ Finder II onto the bracket
and tighten the two thumbscrews (See Figure 6). Then simply

Figure 5. Using the two supplied screws, install the optional

aluminum eyepiece rack in the predrilled holes about halfway down
the left side panel of the base. (XT6 eyepiece rack shown)

Power
knob

Azimuth
adjustment

Altitude
adjustment
knob

Battery
casing

Thumbscrews

knob

Dovetail
mounting
bracket

Figure 6. The EZ Finder II

slide the dovetail mounting bracket into the telescope’s dove­tail mounting base and tighten the thumbscrew on the base to
secure the mounting bracket.

Operation

The EZ Finder II works by projecting a tiny red dot (it’s not a
laser beam) onto a lens mounted in the front of the unit. When
you look through the EZ Finder II, the red dot will appear to
float in space, helping you locate even the faintest of deep
space objects. The red dot is produced by a light-emitting
diode (LED) near the rear of the sight. A 3-volt lithium battery
provides the power for the diode.

Turn the power knob (see Figure 6) clockwise until you hear
the “click” indicating that power has been turned on. Look
through the back of the reflex sight with both eyes open to
see the red dot. Position your eye at a comfortable distance
from the back of the sight. In daylight you may need to cover
the front of the sight with your hand to be able to see the
dot, which is purposefully quite dim. The intensity of the dot
is adjusted by turning the power knob. For best results when
stargazing, use the dimmest possible setting that allows you
to see the dot without difficulty. Typically a dimmer setting is

5

Altitude side bearing

Screw with
round knob

Spring

Phillips-head
screw (black)

Pull loop

Black nylon

spacers

1/4" washer

(black)

Figure 7. Close-up view of the CorrecTension system, which pulls

the tube assembly down onto the altitude bearing pads.

used under dark skies and a bright setting is used under light­polluted skies or daylight.

At the end of your observing session, be sure to turn the power
knob counterclockwise until it clicks off. When the white dots
on the EZ Finder II’s body and power knob are lined up, the EZ
Finder II is turned off.

Installing the CorrecTension (XT) Friction
Optimization System

Perhaps the most exciting feature of the SkyQuest Dobsonians
is the CorrecTension Friction Optimization system. Because of
their light weight, 10" and smaller Dobsonians have always
been plagued by insufficient friction on the altitude bearing
surfaces. As a result, such telescopes move up and down
much too freely. This causes problems when the observer tries
to accurately center and track an object for viewing, especially
at higher powers. Also, the telescope becomes very sensitive
to balance, requiring additional equipment such as counter­weight systems or adjustable side bearings to compensate.

SkyQuest Dobsonians employ a simple yet effective remedy
for the friction problem that obviates the need for such cum­bersome countermeasures. CorrecTension Friction Optimization
utilizes a spring coil to “pull” the tube assembly down onto the
altitude bearing pads, thereby increasing the friction by just
the right amount. With CorrecTension, you can change eye­pieces, or add a barlow lens or solar filter without having to
tediously adjust the telescope’s balance as you would with
other Dobsonians. The altitude friction will roughly equal the
azimuth friction, ensuring optimal performance.

To install the CorrecTension assembly, follow these steps while
referring to Figure 7:

1. Put one of the black nylon spacers on a black Phillips-head
screw. The spacer should be oriented so the narrow end
seats against the head of the screw. Slip one of the black
1/4" washers over the end of the screw. Now, thread the
screw into the hole in the base side panel just below the
cradle. The screw will thread into the preinstalled insert in

a.

b.

Figure 8. (a) To attach the spring to the base, grip the pull loop

with your index finger and pull down on the spring. (b) While pulling
down, slip the end ring of the spring over the bolt head and onto the
narrow part of the nylon spacer, then release the pull loop.

the hole. Use a Phillips screwdriver to tighten the screw.
Repeat this procedure on the opposite side panel.

2. Next, insert one of the screws with a round plastic knob
attached through the end ring of one of the springs. Slip
a black nylon spacer onto the screw. Orient the spacer so
the narrow end is closest to the knob. Thread the entire
assembly into the hole in the center of the telescope’s
altitude side bearing until tight. The end ring of the spring
should seat onto the narrow end of the spacer. Repeat this
procedure for the other altitude side bearing.

3 Attach a pull loop to the free end of each spring. Slide the loop

through the opening in the ring on the end of the spring.

4. Now, pull each spring down using the pull loop, and posi­tion the spring’s end ring over the head of the Phillips
screw (installed in Step 1) and onto the narrow part of the
nylon spacer, as shown in Figure 8b. You needn’t attach
both springs simultaneously; one at a time is fine.

6