ORION TELESCOPES & BINOCULARS SkyQuest XT10 9810 Instruction Manual

IN 179 Rev. B 09/03

Providing Exceptional Consumer Optical Products Since 1975

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INSTRUCTION MANUAL

Orion

®

SkyQuest™ XT10

#9810 Dobsonian Reflecting Telescope

2

Secondary mirror holder with
4-vane spider (not visible)

Navigation knob

Right side panel

Front brace

Handle

Top baseplate

Ground baseplate

Finder scope

Finder scope bracket

Eyepiece

Focus knob

Optical tube

Altitude side bearing

CorrecTension (XT)

Friction Optimization system

Eyepiece rack

Primary

mirror cell

Left side panel

Figure 1. The SkyQuest XT10

Foot (3)

3

Welcome to an exciting new world of adventure! Your SkyQuest XT10 Dobsonian is a high-quality opti-

cal instrument designed to bring you dazzling views of the outer reaches of our universe.With special
new innovations , such as the CorrecTension (XT) Friction Optimization system, large format f ocuser , and
deluxe accessory package, this telescope represents a giant leap forward in the evolution of the
Dobsonian.Whether you are brand-new to amateur astronomy or a seasoned stargazer, the SkyQuest
XT10 Dobsonian will provide many evenings of enjoyment and fascination.

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 . . . . . . . . . . . . .15

7. Specifications . . . . . . . . . . . . . . . . . . . .16

1. Unpacking

The telescope will arrive in two box es, 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) or email sales@tele­scope.com for assistance.

Parts List

Box #1: Optical Tube Assembly and Accessories

Qty. Description
1 Optical tube assembly
1 Dust cover

1 25mm Sirius Plössl eyepiece
1 10mm Sirius Plössl eyepiece
1 9x50 finder scope
1 Finder scope bracket with O-ring
1 4-hole eyepiece rack
1 Collimation cap
2 Eyepiece rack mounting wood screws (length 3/4")
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 knobs 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 screw (length 3")
2 3/8" washers
1 3/8" lock nut
1 Nylon spacer (white)
1T-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)

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.

4

2. Assembly

Now that you hav e unpac k ed the bo xes 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.When tightening screws,
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 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 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 assem­bly 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 cen­ter 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 hex­head 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 pan­els 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 coming 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. Inser t 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 conv enient “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 inter ior 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 fir mly so the adhesive holds the bumper
securely in place.

Figure 2. Exploded view of the Dobsonian base.

C

Figure 3. Position the rubber bumper “stop” over the index mark

on the inside surface of the front brace.

B

L

I

J

D

A

H
E

K

F
G

C

5

Installing the Eyepiece Rack

The aluminum eyepiece rack is a standard accessory on
SkyQuest XT10 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 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 w ood screws and continue tightening the
screws (Figure 4).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.

Placing the Optical Tube on the Dobsonian Base

Lift the optical tube and set the altitude bearings on either side
of the tube in the “cradle” of the base (Figure 5). The unique
flange design of the altitude bearing allows for automatic left-to­right centering of the optical tube in the cradle. 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 finder scope are not in place,
and the CorrecTension system has not been installed.

Installing the CorrecTension (XT) Friction
Optimization System

Perhaps the most exciting new feature of the SkyQuest XT10
Dobsonian is the CorrecTension Friction Optimization system.
Because of their relatively light weight, 10" and smaller
Dobsonians have alwa ys 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 XT10 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 without having to
tediously adjust the telescope’s balance as you w ould with other
Dobsonians.The altitude fr iction will roughly equal the azimuth
friction, ensuring optimal performance.

To install the CorrecTension assembly, follow these steps while
referring to Figure 6:

Figure 4. 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 6. Close-up view of the CorrecTension system.

Black nylon

spacers

1/4" washer

(black)

Altitude side bearing

Screw w/round knob

Spring
Phillips head

screw (black)
Pull loop

Figure 5. 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.”

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 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 round plastic knob
attached through the end ring of one of the springs. Slip a
black nylon spacer onto the screw. Or ient 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 7. You needn’t attach
both springs simultaneously; one at a time is fine.

The CorrecTension system is now installed and engaged. If
you wish to remove the telescope from the base, you will first
need to disconnect the springs from the “posts” on the
Dobsonian base.The spr ings will remain captive on the alti­tude side bearings, so they will not get lost.

Installing the Finder Scope

SkyQuest XT10 Dobsonians come with a high quality, large
aperture 9x50 achromatic crosshair finder scope (Figure 8a)
as standard equipment.This greatly aids in finding objects to
view in the night sky, which will be discussed in detail later.

To place the finder scope in the finder scope bracket, first
unthread the two black nylon thumbscrews until the screw
ends are flush with the inside diameter of the bracket.Place
the O-ring that comes on the base of the bracket over the
body of the finder scope until it seats into the slot on the mid­dle of the finder scope. Slide the eyepiece end (narrow end)
of the finder scope into the end of the bracket’s cylinder oppo-
site the alignment thumbscrews while pulling the chrome,
spring-loaded tensioner on the bracket with your fingers
(Figure 8b). Push the finder scope through the bracket until

6

Figure 7. (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 screw head and onto
the narrow part of the nylon spacer, then release the pull loop.

a.

b.

Figure 8a. The 9x50 finder scope and bracket.

Tensioner

Eyepiece

Nylon

alignment

thumbscrew (2)

Focus lock ring

Finder scope

Finder scope bracket

Figure 8b. Pull back on the tensioner and slide the finder scope

into its bracket until the O-ring is seated in the bracket ring.