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Extendable lens shade
The lens shade on the Express 80mm extends and retracts
along the telescope tube. When viewing through the tele-
scope, make sure the lens shade is extended to block stray
light from entering the telescope, which reduces image con-
trast. Having the shade extended will also provide protection
from dew forming on the objective lens. Retract the lens shade
and attach the objective lens cap for convenient and compact
storage of your telescope.
terrestrial Viewing
Many people enjoy using their telescope to view objects such
as boats, birds and wildlife. The Express 80mm is an excellent
instrument for observing during the daylight hours.
For terrestrial applications, we recommend mounting the
Express 80mm on an altazimuth-style camera tripod or
telescope mount that allows simple vertical (altitude) and hori-
zontal (azimuth) motions. For most telescope mounts, you will
need a 1/4"-20 adapter to couple the scope to the mount head.
Camera tripods come equipped with a 1/4"-20 post, so no
adapter is needed.
Also, most people prefer to use an optional 45° correct-image
diagonal for terrestrial viewing. This provides a comfortable
viewing angle and preserves correct-image orientation.
It’s best to start observing with a low-power eyepiece, because
it offers a wide field of view. With the eyepiece inserted and
secured in the diagonal, simply point the telescope at the sub-
ject you wish to observe. Then look into the eyepiece of the
telescope and center the subject in the field of view. If the view
is blurry, adjust the focus with the focus wheels until the image
appears sharp. For higher magnification, switch to an eyepiece
with a shorter focal length and readjust the focus as neces-
sary. Remember, increasing the magnification decreases the
field of view and the image brightness.
astronomical Viewing
The Express 80mm excels for astronomical observation. Its
unobstructed 80mm aperture and short 480mm focal length
(f/6) provide bright, expansive views of star fields and celestial
objects residing within our solar system and beyond. Once the
Sun sets, there are literally thousands of objects in the night sky
that can be inspected more closely. For astronomical usage,
we recommend a 90° star diagonal instead of a 45° correct-
image diagonal. The 90° star diagonal is more comfortable for
looking up at the higher angles common in astronomical view-
ing. It also provides an increased level of light transmission – a
critical factor when viewing dim objects. Note that when using
a star diagonal, the image in the eyepiece will appear back-
wards (inverted left-to-right).
For casual stargazing, an altazimuth mount will do just fine.
But an equatorial mount is designed to make it easier to manu-
ally “track” the motion of celestial objects in the night sky with
just one slow-motion control cable. Furthermore, with an equa-
torial mount you can add an optional motor drive to track the
stars automatically—a great convenience.
To find celestial 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. A good star chart, atlas, or desktop planetar-
ium software package can come in handy for helping locate
interesting objects among the dizzying multitude of stars over-
head. Except for the Moon and the brighter -planets, it is pretty
time-consuming and frustrating to hunt for objects randomly,
without knowing where to look. It is best to have specific tar-
gets in mind before you begin looking through the eyepiece.
Deep‑sky observing
Under dark skies, you can observe numerous deep-sky
objects with your Express 80mm, including gaseous nebu-
lae, open and globular star clusters, and the brighter galaxies.
Most deep-sky objects are very faint, so it is important you
find an observing site well away from city lights; light-polluted
skies greatly reduce what can be seen with the telescope.
Take plenty of time to let your eyes adapt to the darkness. Use
a red flashlight to see what you’re doing at the telescope, or to
read star charts; red light will not spoil your dark-adapted night
vision as readily as white light will.
Don’t expect these objects to appear like the photographs
you see in books and magazines; most will look like dim gray
“ghosts.” Our eyes are not sensitive enough to see color in
deep-sky objects except in few of the brightest ones. But as
you become more experienced and your observing skills
improve, you will be able to visually coax out more and more
intricate details.
The Express 80mm is optimized to provide bright, high-con-
trast, wide-field views at low magnifications. At first, it might
seem strange to use a telescope for low-power viewing. But
consider very large objects like the Andromeda galaxy, North
America nebula, or Pleiades star cluster. Even at distanc-
es of many light years, they each span angular sizes in the
sky several times that of the full Moon! For objects such as
these, a wide field and bright image are far more important
than magnification. Telescopes with longer focal lengths and
smaller fields may not be able to fit such large objects into
their fields of view. For the best wide-angle views of very large
objects in the Express 80mm, use a 2" eyepiece with a focal
length of about 40mm and an apparent field of 60° or greater.
Deep-sky objects with smaller apparent sizes such as globular
star clusters and planetary nebulae may benefit from higher
magnifications. Experiment with different eyepieces to find the
optimal magnification for a given object.
stars
Stars will appear like twinkling points of light in the telescope.
Even the largest telescopes cannot magnify stars to appear
as anything more than points 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 constel-
lation Lyra and the gorgeous two-color double star Albireo in
Cygnus are favorites. Defocusing the image of a bright star
slightly can help bring out its color.