Providing Exceptional Consumer Optical Products Since 1975
Customer Support (800) 676-1343
E-mail: support@telescope.com
Corporate Offices (831) 763-7000
P.O. Box 1815, Santa Cruz, CA 95061
INSTRUCTION MANUAL
Orion
®
SkyQuest™ XT10
Dobsonian Reflector
#9990
2
W
elcome to an exciting new world of adventure!
Your SkyQuest XT10 Dobsonian is a high-quality optical instrument designed to bring you dazzling views of the outer reaches of our universe.With special
new innov ations, such as the CorrecTension (XT) Friction Optimization system, large f ormat focuser, 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.
Secondary mirror holder with
3-vane spider (not visible)
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
Pull loop
Eyepiece rack
Primary
mirror cell
Left side panel
Figure 1. The SkyQuest XT10 par ts diagram.
Foot (3)
3
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, ha ving 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 box es carefully, as some parts are small.If anything appears to be missing or broken, immediately call Orion
Customer Support (800-676-1343) for assistance.
Parts List
Box #1: Optical Tube Assembly and Accessories
Qty. Description
1 Optical tube assembly
1 Dust cover
1 25mm Plössl eyepiece, 1.25" barrel diameter
1 9mm Plössl eyepiece, 1.25" barrel diameter
1 8x50 finder scope
1 Finder scope bracket
6 Finder scope alignment thumb screws with
knurled lock nuts
1 Moon filter
1 Eyepiece rack
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
1 Handle
2 Socket head cap screws, 5/16" (black)
2 5/16" washers (black)
2 5/16" nuts (black)
1 Large Allen wrench (6mm)
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 Small Allen wrench (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
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.
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
4
2. Assembly
Now that you hav e unpac k ed 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 Allen wrenches.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. Inser t 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 smaller Allen wrench to tighten the screws. 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 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 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 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 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 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 large Allen wrench.
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 inde x mark, as shown in Figure 3.Press
firmly so the adhesive holds the bumper securely in place.
Figure 2. Exploded view of the Dobsonian base.
C
C
B
D
J
A
F
I
H
K
L
E
G
Figure 3. Position the rubber bumper “stop” over the index mark on
the inside surface of the front brace.
5
Installing the Eyepiece Rack
The aluminum eyepiece rack is a standard accessory on
SkyQuest XT10 Dobsonians.It holds four 1.25" ey epieces 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" apar t. Take the
black wood screws that come packaged with the rack, insert
them through the small holes in the rack, and then thread
them into the starter holes with a Phillips screwdriver until
tight (but do not overtighten!). Orient the rack as in Figure 4.
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-to-right 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 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 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 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 6:
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
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
Bolt 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.”
black 1/4" washers o ver 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. 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 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 springs 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 8x50 achromatic crosshair finder scope and a precision metal finder scope bracket as standard equipment.This
greatly aids in finding objects to view in the night sky, which
will be discussed in detail later.
Before attaching the finder scope bracket to the telescope
tube, it is convenient to first install the finder in the bracket.
Thread the six finder scope alignment thumb screws (with
knurled lock nuts attached) into the holes on the outside of
the finder bracket’s rings. Slide the finder scope through the
bracket’s rings and secure it in place with the alignment
thumb screws; make sure the knurled lock nuts are adequately loosened to do this. The finder scope should be
oriented within the finder bracket as shown in Figure 8.
Now , connect the entire assemb ly to the telescope .Do this by
first removing the round knurled nuts on the two threaded
bolts adjacent to the focuser. Then position the holes in the
base of the finder bracket over the bolts, and secure the
bracket in place with the two round n uts.The large (objective)
end of the finder scope should be pointing toward the front
(open) end of the telescope tube.
Inserting an Eyepiece
The final step in the assembly process is to insert an eyepiece into the telescope’s focuser.Take the cover cap off the
end of the focuser drawtube. Loosen the thumb screw on the
1.25" eyepiece adapter (see Figure 9).Do not loosen the two
thumb screws on the 2" eyepiece adapter. Inser t one of the
supplied eyepieces, then secure it by retightening the thumb
screw on the 1.25" eyepiece adapter.The other eyepiece can
be placed in the eyepiece rack until it is needed.
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 8:The 8x50 finder scope and bracket.
Round
knurled nut
Knurled lock nut
Alignment thumb screw
Lock ring
7
The assembly of your SkyQuest Dobsonian is now complete.
It should appear as shown in Figure 1. The dust cap on the
front of the telescope tube should always remain in place
when the telescope is not in use.It is also a good idea to store
eyepieces in an eyepiece case and to replace the cover caps
on the focuser and finder scope when the telescope is idle.
3. Using Your Telescope
It is best to get a feel for the basic functions of the
SkyQuest XT10 Dobsonian during the day, before observing astronomical objects at night. This way you will not
have to fumble around trying to orient yourself in the dark!
Find a spot outdoors where you have plenty of room to
move around the telescope, and where you have a clear
view of some object or vista that is at least 1/4-mile away.
It is not critical that the base be exactly level, but it should
be placed on somewhat flat ground or pavement to ensure
smooth movement of the telescope.
Remember, ne v er point the telescope at or near the Sun without using a proper solar filter over the front aperture!
Altitude and Azimuth
The Dobsonian base of the SkyQuest XT10 permits
motion of the telescope along two axes: altitude (up/down)
and azimuth (left/right) (see Figure 10). This is very convenient, since up/down and left/right are the most “natural”
ways that people aim.As a result, pointing the telescope is
exceptionally easy.
Simply take hold of the telescope tube and move it left or
right so the base rotates about its central azimuth bolt, and
move it up or down so the altitude side bearings rotate in
the base’s cradle. Both motions can be made simultaneously and in a continuous manner for easy aiming. Move
the telescope gently - let it glide. In this way you can point
the telescope to any position in the night sky, from horizon
to horizon.
When moving the telescope, it may be convenient to grasp
the front end of the telescope tube so that your fingers just
protrude into it; this provides a convenient “handle”.
Focusing the Telescope
Insert the low power 25mm eyepiece into the focuser and
secure it with the thumb screw on the 1.25" adapter. Move
the telescope so the front (open) end is pointing in the
general direction of an object at least 1/4-mile away. Now,
with your fingers, slowly rotate one of the focusing knobs
until the object comes into sharp focus. Go a little bit
beyond sharp focus until the image just starts to blur
again, then reverse the rotation of the knob, just to make
sure you’ve hit the exact focus point.
If you have trouble focusing, rotate the focusing knob so
the drawtube is in as far as it will go. Now look through the
eyepiece while slowly rotating the focusing knob in the
opposite direction.You should soon see the point at which
focus is reached.
The black nylon thumb screw on the top of the body of the
focuser (see Figure 9) is to lock the f ocuser dr a wtube in place
once the telescope is properly focused. Before refocusing,
remember to first loosen this thumb screw.
Viewing with Eyeglasses
If you wear eyeglasses, you may be able to keep them on
while you observe, if your eyepieces have enough eye relief
to allow you to see the whole field of view.You can try this by
looking through the eyepiece first with your glasses on and
then with them off, and see if the glasses restrict the view to
only a portion of the full field. If they do, you can easily
Altitude
Azimuth
Figure 10. The SkyQuest has two axes of motion: altitude
(up/down) and azimuth (left/right).
Figure 9:The large format focuser with eyepiece adapters
attached.The focuser will accept eyepieces with barrel
diameters of both 1.25" and 2".
Focus
knob
2"
eyepiece
adapter
Focus
lock
thumb
screw
1.25" eyepiece adapter
8
observe with your glasses off by just refocusing the telescope
the needed amount. If you suffer from severe astigmatism,
however, you may find images noticeably sharper with your
glasses on.
Aligning the Finder Scope
The finder scope must be aligned accurately with the telescope for proper use.To align it, first aim the main telescope
in the general direction of an object at least 1/4-mile away the top of a telephone pole, a chimney, etc. Position that
object in the center of the telescope’s eyepiece.
Now, look in the finder scope. Is the object visible? Ideally, it
will be somewhere in the field of view.If it is not, some coarse
adjustments of the six finder scope alignment thumb screws
will be needed to get the finder scope roughly parallel to the
main tube.
NOTE:The image in both the finder scope and the main telescope will appear upside-down (rotated 180°).This is normal
for finder scopes and reflector telescopes (see Figure 11).
With the image in the finder scope’s field of vie w, you will now
use the six alignment thumb screws to center the object on
the intersection of the crosshairs.
By loosening one alignment thumb screw and tightening another, you change the line of sight of the finder scope.The round,
knurled lock nuts installed on the alignment thumb screws must
be adequately loosened to allow the thumb screws to be
threaded in or out.Continue making adjustments to the various
alignment thumb screws until the image in both the finder
scope and the telescope’s eyepiece is exactly centered.
Check the alignment by moving the telescope to another
object and fixing the finder scope’s crosshairs on the exact
point you want to look at. Then look through the telescope’s
eyepiece to see if that point is centered in the field of view.If it
is, the job is done. If not, make the necessary adjustments
until the two images match up. Once the finder scope is
aligned, turn the lock nuts clockwise until finger-tight to secure
the alignment thumb screws in place.
The finder scope alignment needs to be checked before every
observing session. This can easily be done at night, before
viewing through the telescope.Choose any bright star or planet, center the object in the telescope eyepiece, and then adjust
the finder scope’s alignment thumb screws until the star or
planet is also centered on the finder’s crosshairs. The finder
scope is an invaluable tool for locating objects in the night sky;
its usage for this purpose will be discussed later.
Focusing the Finder Scope
If, when looking through the finder scope, the images appear
somewhat out of focus, you will need to refocus the finder
scope for your eyes. Loosen the lock ring located behind the
objective lens cell on the body of the finder scope (see Figure
8). Back the lock ring off by a few turns, for now.Refocus the
finder scope on a distant object by threading the objective
lens cell in or out on the finder scope body. Precise focusing
will be achieved by focusing the finder scope on a bright star.
Once the image appears sharp, retighten the lock ring behind
the objective lens cell. The finder scope’s focus should not
need to be adjusted again.
Aiming/Pointing the Telescope
With the finder scope aligned, the telescope can be quickly
and accurately pointed at anything you wish to observe.The
finder scope has a much wider field of view than the telescope’s eyepiece, and therefore it is much easier to first
center an object in the finder scope.Then, if the finder scope
is accurately aligned, the object will also be centered in the
telescope’s field of view.
Start by once again moving the telescope until it is pointed in
the general direction of the object you want to see. Some
observers find it convenient to sight along the tube to do this.
Now, look in the finder scope. If your general aim is accurate,
the object should appear somewhere in the field of view.
Make small adjustments to the telescope’s position until the
object is centered on the finder’s crosshairs.Now, look in the
telescope’s eyepiece and enjoy the view!
Magnification
Now that the object you want to view is well centered in the
25mm eyepiece, you may want to increase the magnification
to get a closer view. Loosen the thumb screw on the 1.25"
eyepiece adapter and remove the eyepiece. Place it in the
eyepiece rack, if you wish. Insert the 9mm eyepiece into the
1.25" eyepiece adapter , then retighten the thumb scre w .If you
were careful not to bump the telescope, the object should still
be centered within the field of view. Notice that the object
being viewed is now larger, but somewhat dimmer.
The SkyQuest XT10 is designed to accept any eyepiece with
a barrel diameter of 1.25" or 2". Magnification, or power, is
determined by the focal length of the telescope and the focal
Naked-eye view
Figure 11. The view through a standard finder scope and reflector
telescope is upside down.This is tr ue for the SkyQuest and its finder
scope as well.
View through finder scope and telescope
9
length of the eyepiece.Therefore, by using eyepieces of different focal lengths , the resultant magnification can be v aried.
Magnification is calculated as follows:
Magnification =
Telescope Focal Length (mm)
Eyepiece Focal Length (mm)
The SkyQuest XT10 Dobsonian has a focal length of
1250mm. So, the magnification with the supplied 25mm eyepiece is 1250mm ÷ 25mm = 50x. The magnification provided
by the 9mm eyepiece is 1250mm ÷ 9mm = 139x.
The maximum attainable magnification for a telescope is
directly related to how much light its optics can collect. A telescope with more light collecting area, or aperture, can yield
higher magnifications than a smaller aperture telescope. The
maximum practical magnification for any telescope, regardless of optical design, is about 50x per inch of aperture. This
translates to about 500x for the SkyQuest XT10.
Keep in mind that as magnification is increased, the brightness of the object being viewed will decrease; this is an
inherent principle of the physics of optics and cannot be
avoided. If magnification is doubled, an image appears four
times dimmer. If magnification is tripled, image br ightness is
reduced by a factor of nine!
Note About High Magnifications:
Maximum magnifications are achieved only under the most
ideal viewing conditions at the best observing sites. Most of
the time, magnifications are limited to 200x or less, regardless of aperture. This is because the Earth’s atmosphere
distorts light as it passes through. On nights of good “seeing”,
the atmosphere will be still and will yield the least amount of
distortion. On nights of poor seeing, the atmosphere will be
turbulent, which means different densities of air are rapidly
mixing.This causes significant distortion of the incoming light,
which prevents sharp views at high magnifications.
Tube Balance
Dobsonians are designed to balance with standard supplied
accessories, such as an eyepiece and a finder scope. But
what if you want to use other accessories such as a barlow
lens or a heavy 2" eyepiece? Traditional Dobsonian designs
expect the user to compensate for heavier accessories by
adding weight to the opposite end of the telescope tube.Such
counterweighting systems can be expensive and unwieldy.
The CorrecTension Friction Optimization system of the
SkyQuest XT10 Dobsonian, however, solves the finicky balance problem. The spring coils pull the tube down onto the
base, thereby increasing the friction on the altitude bearing
pads! With CorrecTension, the added weight of small frontend loads will not adversely affect the balance of the
telescope.
If you install an array of heavier accessories onto your
SkyQuest XT10’s optical tube, y ou ma y need at some point to
counterbalance the telescope with a counterweight system.
Carrying the Telescope
Moving the SkyQuest XT10 is easy to do. Remove any eyepieces from the telescope and eyepiece rac k, and place them
in an eyepiece case.You can also remove the finder scope
and finder scope bracket, if you wish. Disengage the
CorrecTension springs by unhooking them from the posts on
the base, using the pull loops.The spr ings remain captive on
the telescope side bearings.The base and tube are now disengaged and can be transported separately.
To carry the base, simply grasp the handle on the front of it.
The tube should be carried with two hands. One way to do
this is to grasp the tube with one hand while grasping the mirror cell end with the other (Figure 12).Another way is to gr asp
the tube with both hands around its circumference (Figure
13). Be careful when setting the tube down on its end so as
not to bend or damage the primary mirror collimation screws
on the bottom of the primary mirror cell.
Figure 13: Another way to carry the tube is to grasp the tube
with both hands around its circumference.
Figure 12: You can carry the tube by grasping the tube with
one hand while grasping the mirror cell end with the other.
10
When putting the SkyQuest into a vehicle, common sense
prevails. It is especially important that the optical tube does
not knock around; this can cause the optics to become misaligned, and could dent the tube. We recommend
transporting and storing the tube assembly in a padded case
for proper protection.
4. Collimation
(Aligning The Mirrors)
Collimation is the process of adjusting the mirrors so they are
perfectly aligned with one another .Y our telescope’s optics were
aligned at the factory, and should not need much adjustment
unless the telescope was handled roughly during shipment.
Accurate alignment is important to ensure the peak performance of your telescope, so it should be checked regularly.
Collimation is relatively easy to do and can be done in daylight.
T o chec k the collimation, remove the e yepiece and look down the
focuser drawtube .Y ou should see the secondary mirror centered
in the drawtube as well as the reflection of the primary mirror
centered in the secondary mirror, and the reflection of the secondary mirror (and your eye) centered in the reflection of the
primary mirror, as in Figure 14a. If anything is off-center, as in
Figure 14b, proceed with the f ollowing the collimation procedure.
It helps to put a piece of white paper on the inside of the optical
tube opposite the focuser. It forms a bright background behind
the secondary mirror, making it easier to distinguish the mirror
holder from the background.
Use a Collimating Tool
To aid in centering your line of sight down the focuser drawtube,
and in centering the mirror reflections during collimation, it is very
helpful to use a precision collimating tool containing crosshairs,
such as the Orion Collimating Eyepiece (#3640). We strongly
recommend that you purchase one.
Alternatively, you can make a crude collimating tool out of an
empty, black plastic 35mm film canister. It will not have
crosshairs, so it won’t be as precise, but it will be better than
nothing. Cut 1/2" from the top lip of the canister and put a 1/16"
to 1/8" diameter hole in the center of its bottom.The film canister
collimating tool goes into the focuser like an eyepiece, with the
bottom end out.
Aligning the Secondary Mirror
With eyepiece removed, look straight down the open focuser
drawtube at the secondary (diagonal) mirror. Ignore the
Figure 14. Collimating the optics. (a) When the mirrors are properly aligned, the view down the focuser drawtube should look like this. (b) If
the optics are out of alignment, the view might look something like this.(c) Here, the secondary mirror is centered under the focuser, but it
needs to be adjusted (tilted) so that the entire primary mirror is visible. (d) The secondary mirror is correctly aligned, but the primary mirror
still needs adjustment.When the primary mirror is correctly aligned, the eye will be centered, as in (a).
a.
b.
c.
d.
reflections for the time being. The secondary mirror itself
should be centered in the focuser drawtube, in the direction
parallel to the length of the telescope. If it isn’t, as in Figure
14b, it must be adjusted.(It helps to adjust the secondary mirror in a brightly lit room with the telescope pointed toward a
bright surface, such as white paper or a wall.) Loosen the
three small alignment screws in the center hub of the secondary mirror holder several turns. Now hold the secondary
mirror holder stationary (be careful not to touch the surface of
the secondary mirror!), while turning the center Phillips head
screw (as in Figure 15). Turning the bolt clockwise will move
the secondary mirror toward the front opening of the optical
tube, while turning the bolt counter-clockwise will move the
secondary mirror toward the primary mirror.
When the secondary mirror is centered in the focuser drawtube, rotate the secondary mirror holder slightly until the
reflection of the primary mirror is as centered in the secondary mirror as it will get. It still may not be perfectly centered,
but that is OK. Now tighten the three alignment screws to
secure the secondary mirror in that position. This adjustment
will rarely need to be done, if ever.
If the entire primary mirror reflection is not visible in the secondary mirror, as in Figure 14c, you will need to adjust the tilt
of the secondary mirror.This is done by alternately loosening
one of the three alignment screws while tightening the other
two, as depicted in Figure 16. The goal is to center the pri-
mary mirror reflection in the secondary mirror, as in Figure
14d. Don’t worry that the reflection of the secondary mirror
(the smallest circle, with your eye reflected in it) is off-center,
you will fix that in the next step.
Adjusting the Primary Mirror
The final adjustment is made to the primary mirror. It will
need adjustment if, as in Figure 14d, the secondary mirror
is centered under the focuser and the reflection of the primary mirror is centered in the secondary mirror, but the
small reflection of the secondary mirror (with your eye
inside) is off-center.
The tilt of the primary mirror is adjusted with three springloaded collimation thumb screws on the back end of the
optical tube (bottom of the primary mirror cell); these are the
larger thumb screws. The other three smaller thumb screws
lock the primary mirror’s position in place; these thumb
screws must be loosened before any collimation adjustments
can be made to the primary mirror.
To start, unthread the thumb screws that lock the primary mirror in place a few turns each (Figure 17).The thumb screws
are slotted, so if they are too difficult to loosen with your fingers, use a flat-head screwdriver.
Now, try tightening or loosening one of the spring-loaded collimation thumb screws one turn (Figure 18). Look into the
focuser and see if the secondary mirror reflection has moved
closer to the center of the primary mirror reflection. Repeat
this process on the other two collimation thumb screws, if
11
Figure 15.To center the secondary mirror under the focuser, hold
the secondary mirror holder in place with your fingers while
adjusting the center screw with a Phillips screwdriver. Do not touch
the mirror’s surface!
Figure 16: Adjust the tilt of the secondar y mirror by loosening
or tightening the three alignment screws with a Phillips
screwdriver.
Figure 17: The three thumb screws that lock the primary
mirror in place must first be loosened before any
adjustments can be made.
Figure 18: The tilt of the pr imar y mirror is adjusted by turning
one or more of the three spring-loaded collimation thumb
screws.
12
necessary .It will take a little trial and error to get a feel for how
to tilt the mirror in this way to center the reflection.(It helps to
have two people for primary mirror collimation, one to look in
the focuser while the other adjusts the collimation thumb
screws.) Do not loosen (i.e., rotate counter-clockwise) each
collimation thumb screw too much, or the thumb screw will
completely unthread from the mirror cell. Rather, try tightening the other two collimation thumb screws.
Once the secondary mirror reflection is centered in the primary mirror reflection, retighten the thumb screws that lock
the primary mirror’s position in place.
The view through the focuser should now resemble Figure
14a;the reflection of the primary mirror is centered in the secondary mirror, and the reflection of the secondary mirror is
centered in the reflection of the primary mirror.
A simple star test will tell you whether the optics are accurately collimated.
Star-Testing the Telescope
When it is dark, point the telescope at a bright star and accurately center it in the eyepiece’s field-of-view. Slowly defocus
the image with the focusing knob. If the telescope is correctly
collimated, the expanding disk should be a perfect circle
(Figure 19). If the image is unsymmetrical, the scope is out of
collimation. The dark shadow cast by the secondary mirror
should appear in the very center of the out-of-focus circle, like
the hole in a doughnut.If the “hole”appears off-center, the telescope is out of collimation.
If you try the star test and the bright star you have selected is not accurately centered in the eyepiece, then the
optics will always appear out of collimation, even though
they may be perfectly aligned. It is critical to keep the star
centered, so over time you will need to make slight corrections to the telescope’s position in order to account for the
sky’s apparent motion.
5. Astronomical Observing
For many users, the SkyQuest XT10 telescope will be a
major leap into the world of amateur astronomy.This section
is intended to get you ready for your voyages through the
night sky.
Observing Tips
A. Site Selection
Pick a location awa y from street lights and bright yard lighting.
Avoid vie wing o v er rooftops and chimneys , as the y often ha v e
warm air currents rising from them, which distort the image
seen in the eyepiece. Similarly, you should not observe
through an open window from indoors. Better yet, choose a
site out-of-town, away from any “light pollution”. You’ll be
stunned at how many more stars you’ll see! Most importantly, make sure that any chosen site has a clear view of a large
portion of the sky.
B. Seeing and Transparency
Atmospheric conditions play a huge part in quality of viewing. In conditions of good “seeing”, star twinkling is minimal
and objects appear steady in the eyepiece. Seeing is best
overhead, worst at the horizon. Also, seeing generally gets
better after midnight, when much of the heat absorbed by
the Earth during the day has radiated off into space.
Typically, seeing conditions will be better at sites that have
an altitude over about 3000 feet. Altitude helps because it
decreases the amount of distortion causing atmosphere you
are looking through.
A good way to judge if the seeing is good or not is to look at
bright stars about 40° above the horizon. If the stars appear
to “twinkle”, the atmosphere is significantly distorting the
incoming light, and views at high magnifications will not
appear sharp. If the stars appear steady and do not twinkle,
seeing conditions are probably good, and higher magnifications will be possible.
Also, seeing conditions are typically poor during the day. This
is because the heat from the Sun warms the air and causes
turbulence.
Good “transparency” is especially important for observing
faint objects. It simply means the air is free of moisture,
smoke, and dust. All tend to scatter light, which reduces an
object’s brightness.
C. Cooling the Telescope
All optical instruments need time to reach “thermal equilibrium” to achieve maximum stability of the lenses and mirrors,
which is essential for peak performance.When moved from a
warm indoor location outside to cooler air (or vice-versa), a
telescope needs time to cool to the outdoor temperature.The
bigger the instrument and the larger the temperature change,
the more time will be needed.
Allow at least 30 minutes for your SkyQuest XT10 to equilibrate. If the scope has more than a 40° temperature
adjustment, allow an hour or more.In the winter, storing the
telescope outdoors in a shed or garage greatly reduces the
amount of time needed for the optics to stabilize.It also is a
good idea to keep the scope covered until the Sun sets so
the tube does not heat greatly above the temperature of the
outside air.
Figure 19: A star test will determine if a telescope’s optics are
properly collimated. An unfocused view of a bright star through the
eyepiece should appear as illustrated on right if optics are perfectly
collimated. If circle is unsymmetrical, as in illustration on left,
scope needs collimation.
Out of collimation Collimated
13
D. Let Your Eyes Dark-Adapt
Do not expect to go from a lighted house into the darkness of
the outdoors at night and immediately see faint nebulas,
galaxies, and star clusters- or even very many stars, for that
matter. Your eyes take about 30 minutes to reach perhaps
80% of their full dark-adapted sensitivity. Many observers
notice improvements after several hours of total darkness. As
your eyes become dark-adapted, more stars will glimmer into
view and you will be able to see fainter details in objects you
view in your telescope.Exposing your eyes to very bright daylight for extended periods of time can adversely affect your
night vision for days. So give yourself at least a little while to
get used to the dark before you begin observing.
To see what you are doing in the darkness, use a red-filtered
flashlight rather than a white light. Red light does not spoil
your eyes’ dar k adaptation like white light does. A flashlight
with a red LED light is ideal, or you can cover the front of a
regular incandescent flashlight with red cellophane or paper.
Beware, too, that nearby porch and streetlights and automobile headlights will spoil your night vision.
Tracking Celestial Objects
The Earth is constantly rotating about its polar axis, completing one full rotation every 24 hours; this is what defines a
“day”.We do not feel the Earth rotating, but we can tell that it
is at night by seeing the apparent movement of stars from
east to west.This movement translates into a rate of .25° per
minute, or 15 arc-seconds per second.(There are 60 arc-minutes in 1°, and 60 arc-seconds in one arc-minute.) This is
called the sidereal rate.
When you observe any astronomical object, you are watching
a moving target.This means the telescope’s position must be
slowly updated over time to k eep an object in the field of vie w.
To keep the object in the telescope’s field of view (to “track”
it), the telescope must be moved by small increments every
now and then, in the direction the object is moving. This is
easy to do with a SkyQuest XT10 Dobsonian because of its
buttery smooth motion on both axes.As the object moves off
toward the edge of the field of view, you just lightly nudge the
telescope to bring it back to the center.
You will notice that it is more difficult to track objects when the
telescope tube is aimed nearly straight up.This is inherent to
the basic design of the Dobsonian, and stems from the fact
that there is very little leverage to move in azimuth when the
tube is in a near-vertical position. To gain more leverage, try
grasping the tube close to the altitude side bearings with both
hands. Also, when looking overhead, if the telescope cannot
be moved any more in altitude, rotate the telescope 180° in
azimuth to continue motion.
Remember that objects appear to move across the field of
view faster at higher magnifications.This is because the field
of view becomes narrower.
Eyepiece Selection
By using eyepieces of varying focal lengths, it is possible to
attain many magnifications with the SkyQuest XT10
Dobsonian.The telescopes come with two high-quality Plossl
eyepieces: a 25mm, which gives a magnification of 50x, and
a 9mm, which gives a magnification of 139x.Other eyepieces
can be used to achieve higher or lower powers. It is quite
common for an observer to own five or more eyepieces to
access a wide range of magnifications. This allows the
observer to choose the best eyepiece to use depending on
the object being viewed. At least to begin with, the two supplied eyepieces will suffice nicely.
Whatever you choose to view, always start by inser ting your
lowest power (longest focal length) eyepiece to locate and
center the object. Low magnification yields a wide field of
view, which shows a larger area of sky in the eyepiece.This
makes acquiring and centering an object much easier. If you
try to find and center objects with high power (narrow field of
view), it’s like trying to find a needle in a haystack!
Once you’ve centered the object in the eyepiece, you can
switch to higher magnification (shorter focal length eyepiece),
if you wish. This is especially recommended for small and
bright objects, like planets and double stars.The Moon also
takes higher magnifications well.
Deep-sky objects, howe ver, typically look better at medium or
low magnifications. This is because many of them are quite
faint, yet have some extent (apparent width). Deep-sky
objects will often disappear at higher magnifications, since
greater magnification inherently yields dimmer images.This is
not the case for all deep-sky objects, how ever.Many galaxies
are quite small, yet are somewhat bright, so higher power
may show more detail.
The best rule of thumb with eyepiece selection is to start with
a low power, wide field, and then work your way up in magnification. If the object looks better, try an even higher
magnification. If the object looks worse, then back off the
magnification a little by using a lower power eyepiece.
Use of 2" Eyepieces
The SkyQuest XT10 comes with a large format focuser
(Figure 9) as standard equipment. Because of its large size,
it is able to accept eyepieces that have a 2" barrel diameter.
2" eyepieces are desirable because they allow for a wider
field of view than 1.25" eyepieces. Many observers own at
least one 2" eyepiece to yield the largest field of view possible for looking at wide deep sky objects, such as open star
clusters and gaseous nebulae. 2" eyepieces can also give
nice views of the Moon.
To use a 2" eyepiece, simply remove the 1.25" eyepiece
adapter from the end of the focuser drawtube. You must first
loosen the two thumb screws on the 2" eyepiece adapter to
do this.Now, insert a 2" eyepiece into the focuser, and secure
it with the two thumb screws. Focus the eyepiece as
described previously.
You’ll be stunned at the wide fields of view that 2" eyepieces can deliver. It makes you feel like you’re floating
through space!
Objects to Observe
Now that you are all set up and ready to go, one critical decision must be made: what to look at?
14
A. The Moon
With its rocky surface, the Moon is one of the easiest and
most interesting targets to view with your telescope. Lunar
craters, marias, and even mountain ranges can all be clearly seen from a distance of 238,000 miles away! With its
ever-changing phases, you’ll get a new view of the Moon
every night.The best time to observe our one and only natural satellite is during a partial phase, that is, when the Moon
is NOT full. Dur ing partial phases, shadows are cast on the
surface, which reveal more detail, especially right along the
border between the dark and light portions of the disk (called
the “terminator”). A full Moon is too bright and devoid of surface shadows to yield a pleasing view.Make sure to observe
the Moon when it is well above the horizon to get the
sharpest images.
Use the included Moon filter to dim the Moon when it is very
bright. It simply threads onto the bottom of the eyepieces
(you must first remove the eyepiece from the focuser to
attach a filter).You’ll find that the Moon filter improves viewing comfort, and also helps to bring out subtle features on
the lunar surface.
B. The Sun
You can change your nighttime telescope into a daytime Sun
viewer by installing an optional full-aperture solar filter over
the front opening of a SkyQuest XT10.The primary attraction
is sunspots, which change shape, appearance, and location
daily. Sunspots are directly related to magnetic activity in the
Sun. Many observers like to make drawings of sunspots to
monitor how the Sun is changing from day to day.
Important Note: Do not look at the Sun with any optical instrument without a professionally made solar filter , or permanent ey e
damage could result.
C. The Planets
The planets don’t stay put like the stars, so to find them you
should refer to Sky Calendar at our website (www.telescope.com), or to charts published monthly in Astronomy,
Sky & Telescope, or other astronomy magazines. Venus,
Mars, Jupiter, and Saturn are the brightest objects in the sky
after the Sun and the Moon.Your SkyQuest XT10 is capable
of showing you these planets in some detail. Other planets
may be visible but will likely appear starlike. Because planets
are quite small in apparent size, optional higher power eyepieces are recommended and often needed for detailed
observations. Not all the planets are generally visible at any
one time.
JUPITER The largest planet, Jupiter, is a great subject for
observation. You can see the disk of the giant planet and
watch the ever-changing positions of its four largest moons Io, Callisto, Europa, and Ganymede. Higher power eyepieces
should bring out the cloud bands on the planet’s disk.
SATURN The ringed planet is a breathtaking sight when it is
well positioned.The tilt angle of the rings varies over a period
of many years; sometimes they are seen edge-on, while at
other times they are broadside and look like giant “ears” on
each side of Saturn’s disk. A steady atmosphere (good see-
ing) is necessary for a good view. You will probably see a
bright “star” close by, which is Saturn’s brightest moon, Titan.
VENUS At its brightest, Venus is the most luminous object in
the sky, excluding the Sun and the Moon. It is so bright that
sometimes it is visible to the naked eye during full daylight!
Ironically, Venus appears as a thin crescent, not a full disk,
when at its peak brightness.Because it is so close to the Sun,
it never wanders too far from the morning or evening horizon.
No surface markings can be seen on Venus, which is always
shrouded in dense clouds.
MARS The Red Planet makes its closest approach to Earth
every two years. During close approaches you’ll see a red
disk, and may be able to see the polar ice cap.To see surface
detail on Mars, you will need a high power eyepiece and very
steady air!
D. The Stars
Stars will appear like twinkling points of light. Even powerful telescopes cannot magnify stars to appear as more
than a point of light! You can, however, enjoy the different
colors of the stars and locate many pretty double and multiple stars. The famous “Double-Double” in the
constellation Lyra and the gorgeous two-color double star
Albireo in Cygnus are favorites. Defocusing a star slightly
can help bring out its color.
E. Deep-Sky Objects
Under dark skies, you can observe a wealth of fascinating
deep-sky objects, including gaseous nebulas, open and globular star clusters, and a variety of different types of galaxies.
Most deep-sky objects are very faint, so it is important that
you find an observing site well away from light pollution.Take
plenty of time to let your eyes adjust to the darkness.Do not
expect these subjects to appear like the photogr aphs y ou see
in books and magazines; most will look like dim gray
smudges. (Our eyes are not sensitive enough to see color in
deep-sky objects except in a few of the brightest ones.) But
as you become more experienced and your observing skills
get sharper, you will be able to ferret out more and more subtle details and structure.
How to Find Deep-sky Objects: Starhopping
Starhopping, as it is called by astronomers, is perhaps the
simplest way to hunt down objects to view in the night sky. It
entails first pointing the telescope at a star close to the object
you wish to observe, and then progressing to other stars closer and closer to the object until it is in the field of view of the
eyepiece. It is a very intuitive technique that has been
employed for hundreds of years by professional and amateur
astronomers alike. Keep in mind, as with any new task, that
starhopping may seem challenging at first, but will become
easier over time and with practice.
To starhop, only a minimal amount of additional equipment is
necessary. A star chart or atlas that shows stars to at least
magnitude 5 is required. Select one that shows the positions
of many deep-sky objects, so you will have a lot of options to
choose from. If you do not know the positions of the constel-
15
lations in the night sky, you will need to get a planisphere to
identify them.
Start by choosing bright objects to view.The brightness of an
object is measured by its visual magnitude; the brighter an
object, the lower its magnitude.Choose an object with a visual magnitude of 9 or lower. Many beginners start with the
Messier objects, which represent some of the best and brightest deep-sky objects, first catalogued about 200 years ago by
the French astronomer Charles Messier.
Determine in which constellation the object lies. Now, find the
constellation in the sky. If you do not recognize the constellations on sight, consult a planisphere. The planisphere gives
an all-sky view and shows which constellations are visible on
a given night at a given time.
Now, look at your star chart and find the brightest star in the
constellation that is near the object you are trying to find.
Using the finder scope, point the telescope at this star and
center it on the crosshairs. Next, look again at the star char t
and find another suitably bright star near the bright star currently centered in the finder. Keep in mind that the field of
view of the finder scope is approximately 5°, so you should
choose another star that is no more that 5° from the first star,
if possible. Move the telescope slightly, until the telescope is
centered on the new star.
Continue using stars as guideposts in this way until you are
at the approximate position of the object you are trying to find
(Figure 20). Look in the telescope’s eyepiece, and the object
should be somewhere within the field of view.If it’s not, s weep
the telescope carefully around the immediate vicinity until the
object is found.
If you have trouble finding the object, start the starhop again
from the brightest star near the object you wish to view. This
time, be sure the stars indicated on the star chart are in fact
the stars you are centering in the eyepiece. Remember, the
finder scope (and main telescope eyepiece, for that matter)
gives an inverted image, so you must keep this in mind when
starhopping from star to star.
Note About Astrophotography
SkyQuest XT10 Dobsonians are designed for visual, not photographic, use. The Dobsonian mount is not an equatorial
type mount, so it cannot be motor driven for long exposure
astrophotography. SkyQuests have also been optically optimized for visual use, since photographic optimization
degrades visual performance.
6. Care and Maintenance
If you give your telescope reasonable care, it will last a lifetime. Store it in a clean, dr y, dust-free place, safe from rapid
changes in temperature and humidity. Do not store the telescope outdoors, although storage in a garage or shed is OK.
Small components like eyepieces and other accessories
should be kept in a protective box or storage case. Keep the
cap on the front of the telescope when it is not in use.
The telescope requires very little mechanical maintenance.
The optical tube is steel and has a smooth painted finish that
is fairly scratch-resistant. If a scratch does appear on the
tube, it will not harm the telescope.If you wish, you ma y apply
some auto touch-up paint to the scratch. Smudges on the
tube can be wiped off with a soft cloth and a household
cleaner such as Windex or Formula 409.
Cleaning Lenses
Any quality optical lens cleaning tissue and optical lens cleaning fluid specifically designed for multi-coated optics can be
used to clean the exposed lenses of your eyepieces or finder
scope. Never use regular glass cleaner or cleaning fluid
designed for eyeglasses. Before cleaning with fluid and tissue, however, blow any loose particles off the lens with a
blower bulb or compressed air. Then apply some cleaning
fluid to a tissue, never directly on the optics. Wipe the lens
gently in a circular motion, then remove any excess fluid with
a fresh lens tissue. Oily fingerprints and smudges may be
removed using this method. Use caution; rubbing too hard
may scratch the lens. On larger lenses, clean only a small
area at a time, using a fresh lens tissue on each area. Never
reuse tissues.
Cleaning Mirrors
You should not have to clean the telescope’s mirrors very often;
normally once every year or so.Covering the telescope with the
dust cap when it is not in use will prevent dust from accumulating on the mirrors. Improper cleaning can scratch mirror
coatings, so the fewer times you have to clean the mirrors, the
better. Small specks of dust or flecks of paint have virtually no
effect on the visual performance of the telescope.
Figure 20. Starhopping is a good way to locate hard-to-find
objects. Refer to a star chart to map a route to the object that uses
bright stars as guideposts. Center the first star you’ve chosen in
the finder scope and telescope eyepiece (1). Now move the scope
carefully in the direction of the next bright star (2), until it is
centered. Repeat (3 and 4). The last hop (5) should place the
desired object in the eyepiece.
The large primary mirror and the elliptical secondar y mirror
of your telescope are front-surface aluminized and overcoated with hard silicon monoxide, which prevents the
aluminum from oxidizing. These coatings normally last
through many years of use before requiring re-coating
(which is easily done).
To clean the secondary mirror, first remov e it from the telescope.
Do this by keeping the secondary mirror holder stationary with
your fingers while unthreading the center Phillips head screw in
the hub of the 3-vaned spider .The entire mirror holder will come
out of the telescope. The secondary mirror itself cannot be
removed from the holder because it is glued into place.Handle
the entire assembly carefully by the holder only;do not touch the
mirror surface.You can clean the secondary mirror in its holder
by following the same procedure described below for cleaning
the primary mirror.
To clean the primary mirror, carefully remove the mirror cell from
the telescope.This is done by removing the six screws that connect the entire mirror cell to the steel tube. These screws are
located on the outside of the tube, just above the mirror
cell casting.
Now, remove the mirror from the mirror cell by first removing the
four mirror clips that secure the mirror in its cell. Use a Phillips
screwdriver to unthread the mirror clip anchor screws.Next, hold
the mirror by its edge, and remov e it from the mirror cell.Be careful not to touch the aluminized surface of the mirror with your
fingers! Set the mirror on a clean, soft towel.Fill a clean sink, free
of abrasive cleanser, with room-temperature water, a few drops
of liquid dishwashing detergent, and if possible, a cap-full of rubbing alcohol. Submerge the mirror (aluminized face up) in the
water and let it soak for several minutes (or hours if it’s a very
dirty mirror).Wipe the mirror under water with clean cotton balls,
using extremely light pressure and stroking in straight lines
across the surface.Use one ball for each wipe across the mirror.
Then rinse the mirror under a stream of lukewarm water. Any
particles on the surface can be swabbed gently with a series of
clean cotton balls, each used just one time. Dr y the mirror in a
stream of air (a “blower bulb” works great), or remove any stray
drops of water with the corner of a paper towel.Water will run off
a clean surface.Dry the bottom and edge surfaces with a towel
(not the mirror surface!). Cover the mirror surface with Kleenex,
and leave the entire assembly in a warm area until it is completely dry before reassembling the telescope.
7. Specifications
SkyQuest XT10
Focal Length: 1250mm
Aperture: 250mm
Focal Ratio: f/5
Mirror Coatings: aluminum with SiO overcoat, 88% reflective
Minor Axis of Secondary Mirror: 63mm
Weight: 57.6 lbs. (tube 35.0 lbs., base 22.6 lbs.)
Tube Length: 1220mm (48")
Tube Outer Diameter: 303mm
One-Year Limited Warranty
This Orion SkyQuest XT Dobsonian Reflecting Telescope is warranted against defects in materials or workmanship for
a period of one year from the date of purchase.This warranty is for the benefit of the original retail purchaser only.During
this warranty period Orion Telescopes & Binoculars will repair or replace, at Orion’s option, any warranted instrument
that proves to be defective, provided it is returned postage paid to: Orion Warranty Repair, 89 Hangar Way, Watsonville,
CA 95076. If the product is not registered, proof of purchase (such as a copy of the original invoice) is required.
This warranty does not apply if, in Orion’s judgment, the instrument has been abused, mishandled, or modified, nor
does it apply to normal wear and tear.This warranty gives you specific legal rights, and y ou may also have other rights,
which vary from state to state. For further warranty service information, contact: Customer Service Department, Orion
Telescopes & Binoculars, P. O. Box 1815, Santa Cruz, CA 95061; (800) 676-1343.
Orion Telescopes & Binoculars
Post Office Box 1815, Santa Cruz, CA 95061
Customer Support Help Line (800) 676-1343 • Day or Evening
Loading...