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focuser and see if the secondary mirror reflection has moved
closer to the center of the primary. You can tell this easily with
the collimation cap and mirror center mark by simply watch-
ing to see if the “dot” of the collimation cap is moving closer
or further away from the “ring” on the center of the primary
mirror mark. When you have the dot centered as much as is
possible in the ring, your primary mirror is collimated. The
view through the collimation cap should resemble Figure 14e.
Re-tighten the locking thumbscrews.

A simple star test will tell you whether the optics are accu-
rately collimated.

Note About the Collimatable 2" Focuser (XT8)

The 2" focuser  of the SkyQuest XT8 can be collimated using
three pairs of push-pull screws located at the base of the
focuser. The focuser was collimated at the factory however,
and should never need to be adjusted. Focuser collimation is
only required under very rare circumstances, but has been
made available for this telescope should such a need arise.

Star-Testing the Telescope

When it is dark, point the telescope at a bright star and accu-
rately 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 tel-
escope 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 tele-
scope’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 intend-
ed to get you ready for your voyages through the night sky.

Observing Tips

A. Site Selection

Pick a location away from street lights and bright yard light-
ing. Avoid viewing over rooftops and chimneys, as they often
have 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 over-
head, 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 magnifica-
tions 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 equilibri-
um” 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

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

Summary of Contents for SkyQuest XT10 9810

Page 1: ...nal 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 9810 Dobsonian Reflecting Telescope ...

Page 2: ... 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 ...

Page 3: ...s in the Parts List below are present Be sure to check boxes carefully as some parts are small If any thing appears to be missing or broken immediately call Orion Customer Support 800 676 1343 or email sales tele scope 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 eye...

Page 4: ...ace 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 l...

Page 5: ...ng 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 vie...

Page 6: ...cope 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 alti tude 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 ...

Page 7: ...t 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 navigati...

Page 8: ... located behind the objective lens cell on the body of the finder scope see Figure 8a 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 objecti...

Page 9: ...ystems can be expensive and unwieldy The CorrecTension Friction Optimization system of the SkyQuest XT10 Dobsonian however solves the finicky bal ance 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 front end loads will not adversely affect the balance of the telescope If you install...

Page 10: ...rk it yourself Note The center ring sticker need not ever be removed from the primary mirror Because it lies directly in the shadow of the secondary mirror its presence in no way adversely affects the optical performance of the tele scope or the image quality That might seem counterintuitive but its true Aligning the Secondary Mirror With the collimation cap in place look through the hole in the c...

Page 11: ...n tered 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 the dot of the colli mation cap is off center The tilt of the primary mirror is adjusted with three spring loaded collimation thumbscrews on the back end of the optical tube bottom of the primary mirror cell these are the larger thumbscrews Th...

Page 12: ...uld 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...

Page 13: ...ide 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 ma...

Page 14: ...faint stars The brightest is the 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...

Page 15: ...hy SkyQuests have also been optically opti mized for visual use since photographic optimization degrades visual performance With that in mind however it is possible to do some simple astrophotography with a SkyQuest With the use of afocal photography techniques where the camera is simply placed to the eyepiece to take a picture and digital cameras it is possible to take pictures of bright objects ...

Page 16: ...nthread the mirror clip anchor screws Next hold the mirror by its edge and remove it from the mir ror 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 temper ature water a few drops of liquid dishwashing detergent and if possible a cap full of rubbing alcohol Submerge the m...

Page 17: ...17 ...

Page 18: ...r 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 you may also have other rights which vary from state to state F...

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