Orion SKYQUEST XT8 - Manual (Page 16)

SkyQuest XT8 and XT10 models are designed to accept
an optional Orion Cooling Accelerator Fan (#7814). When
attached to the rear cell of the telescope, the fan hastens the
equilibration of the primary mirror to ambient temperature.
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 day-
light 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’ dark 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.
Dim light is preferable to bright light. Beware, too, that nearby
porch and streetlights and automobile headlights will spoil
your night vision.
Eyepiece selection
By using eyepieces of different focal lengths, it is possible to
attain many different magnifications with your telescope. The
telescope comes with two high-quality Sirius Plössl eyepiec-
es: a 25mm focal length, which provides a magnification of
48x, and a 10mm focal length, which provides a magnification
of 120x. 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 inserting 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, however, 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, however. Many galax-
ies 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.
a. the Moon
With is rocky and cratered surface, the Moon is one of the
most interesting and easy subjects to view with your scope.
The best time to view it is during its partial phases when
shadows fall on the craters and canyon walls to give them
definition. While the full moon may look like a tempting target,
it is not optimal for viewing! The light is too bright and surface
definition is low.
Even at partial phases the Moon is very bright. Use of an
optional Moon filter to helps to dim the glare. It simply threads
onto the bottom of the eyepiece. You’ll find the Moon filter
improves viewing comfort, and helps bring out the subtle fea-
tures of 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 the telescope. 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 eye damage could result. Also, be sure to cover
the finder scope, or better yet, remove it altogether.
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 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 IntelliScope 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 recom-
mended 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 moon:
Io, Callisto, Europa, and Ganymede. Higher power eyepieces
should bring out the cloud bands on the planet’s disk and the
Great Red Spot.
SATURN The ringed planet is a breathtaking sight. The tilt
angle of the rings varies over a period of many years; some-
times they are seen edge-on, while at other times they are
broadside and look like giant “ears” on each side of Saturn’s
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