Orion SKYVIEW PRO 120 EQ Instruction Manual page 13

tion outside to cooler air (or vice-versa), a telescope needs
time to cool to the outdoor temperature. The bigger the instru-
ment and the larger the temperature change, the more time
will be needed.
Allow at least 30 minutes for your SkyView Pro 120 EQ 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.
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, gal-
axies, and star clusters- or even very many stars, for that mat-
ter. 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. So give yourself at least a little while to get
used to the dark before you begin observing. Also, exposing
your eyes to very bright daylight for extended periods of time
can adversely affect your night vision for days.
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.
Beware, too, that nearby porch and streetlights and automo-
bile headlights will spoil your night vision.
Eyepiece Selection
By using eyepieces of varying focal lengths, it is possible to
attain many magnifications with the SkyView Pro 120 EQ. The
telescope comes with two high-quality Sirius Plössl eyepiec-
es: a 25mm, which gives a magnification of 40x, and a 10mm,
which gives a magnification of 100x. 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 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 magnifi-
cation. If the object looks better, try an even higher magnifica-
tion. If the object looks worse, then back off the magnification
a little by using a lower power eyepiece.
What to Expect
So what will you see with your telescope? You should be able
to see bands on Jupiter, the rings of Saturn, craters on the
moon, the waxing and waning of Venus, and possibly hun-
dreds of deep sky objects. Do not expect to see as much color
as you in NASA photos, since those are taken with long-expo-
sure cameras and have "false color" added. Our eyes are not
sensitive enough to see color in deep-sky objects except in a
few of the brightest ones.
Remember that you are seeing these objects using your own
telescope with your own eyes! The object you see in your
eyepiece is in real-time, and not some conveniently provided
image from an expensive space probe. Each session with
your telescope will be a learning experience. Each time you
work with your telescope it will get easier to use, and stellar
objects will become easier to find. Take it from us, there is
big difference between looking at a well-made full-color NASA
image of a deep-sky object in a lit room during the daytime,
and seeing that same object in your telescope at night. One
can merely be a pretty image someone gave to you. The other
is an experience you will never forget!
A. The Moon
With is rocky and cratered surface, the moon is one of the
most interesting and easy subjects for your scope. The best
time to view it is during its partial phases when shadows fall
on the craters and canyon walls to give its features definition.
While the full moon may look like a tempting target, it is actu-
ally the worst time for viewing! The light of a full moon is too
bright and lacks any decent surface definition.
Use an optional Moon filter to dim the Moon when it is very
bright. It simply threads onto the bottom of the eyepiece from
the focuser (you must first remove the eyepiece from the diag-
onal to attach the filter). You'll find the Moon filter improves
viewing comfort, and helps bring out the subtle features if 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 SkyView Pro 120 EQ. The primary attrac-
tion is sunspots, which change shape, appearance, and loca-
tion 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.
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