12
Keep in mind that as you increase magnification, the bright-
ness of the object viewed will decrease; this is an inherent
principle of the laws of physics and cannot be avoided. If mag-
nification is doubled, an image appears four times dimmer.
If magnification is tripled, image brightness is reduced by a
factor of nine!
Start by centering the object you wish to see in the 25mm
eyepiece. Then you may want to increase the magnification
to get a closer view, by switching to the 10mm eyepiece. If
the object is off-center (i.e., it is near the edge of the field of
view) you will lose it when you increase magnification, since
the field of view will be narrower with the higher-powered
eyepiece. So make sure it is centered in the 25mm eyepiece
before switching to the 10mm eyepiece.
Focusing the Telescope
To focus the telescope, turn the focus wheels (
Figure 17)
forward or back until you see your target object (e.g., stars,
the Moon, etc.) in the eyepiece. Then make finer adjustments
until the image is sharp. If you’re having trouble achieving ini-
tial focus, rack the focuser drawtube all the way in using the
focus wheels, then while looking into the eyepiece slowly turn
the focus wheels so that the drawtube extends outward. Keep
going until you see your target object come into focus. Note
that when you change eyepieces you may have to adjust the
focus a bit to get a sharp image with the newly inserted eye-
piece.
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 many bright
deep-sky objects. Do not expect to see color as you do in
NASA photos, since those are taken with long-exposure cam-
eras 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.
Objects to Observe
Now that you are all set up and ready to go, what is there to
look at in the night sky?
A. The Moon
With its rocky surface, the Moon is one of the easiest and most
interesting objects to view with your telescope. Lunar craters,
maria, 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 dur-
ing a partial phase, that is, when the Moon is not full. During
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 an optional 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 helps to bring out subtle features on the lunar surface.
B. The Planets
The planets don’t stay put like the stars, so to find them you
should refer to the monthly star charts at OrionTelescopes.
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. Other planets may be visible but will likely
appear star-like. Because planets are quite small in apparent
size, optional higher-power eyepieces or a Barlow lens are
recommended and often needed for detailed observations.
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 sun-
spots, 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 instru-
ment without a professionally made solar filter, or permanent
eye damage could result.
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 gor-
geous 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 globu-
lar star clusters, and different types of galaxies. Most deep-sky
objects are very faint, so it is important you find an observing
site well away from light pollution.
To find deep-sky objects with your telescope, you first need
to become reasonably familiar with the night sky. Unless you
know how to recognize the constellation Orion, for instance,
you won’t have much luck locating the Orion Nebula. A simple
planisphere, or star wheel, can be a valuable tool for learning
the constellations and seeing which ones are visible in the sky
on a given night. Once you have identified a few constellations,
a good star chart, atlas, or astronomy app will come in handy
for helping locate interesting deep-sky objects to view within
the constellations.
Do not expect these objects to appear like the photographs
you see in books and on the internet; 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.
