INSTRUCTION MANUAL
Orion® Express™ 80mm
Refractor Telescope
#9780 Optical Tube Assembly
Providing Exceptional 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
IN 259 Rev. A 6/05
Objective lens
1.25" Eyepiece adapter
Focuser drawtube
Focuser rotation thumbscrew
Lens shade
Focus wheel
Mounting block
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Figure 1. The Express 80mm optical tube assembly.
Welcome to a new world of adventure! Your Orion Express 80mm is a fine-quality instrument designed
for both daytime terrestrial viewing and nighttime stargazing. Compact, portable, and easy to use, this
versatile scope will provide many hours of enjoyment for the whole family.
These instructions will help you set up and properly use and care for your telescope. Please read them
over thoroughly before getting started.
and remove the 1.25" eyepiece adapter. Insert a 2" diagonal
into the drawtube and secure it in place with the drawtube’s
Parts List
Qty. Description
1 Optical tube assembly
1 1.25" Eyepiece adapter (comes installed in focuser
drawtube)
1 Carry case
1 Objective lens cover
thumbscrew. Insert a 2" eyepiece (or 1.25" eyepiece, using
the 1.25" eyepiece adapter) into the diagonal and secure it in
place with the thumbscrew(s) on the diagonal. (Always loosen
thumbscrews before rotating or removing the diagonal or an
eyepiece.) To use a 1.25" diagonal and eyepieces, secure the
1.25" eyepiece adapter in the focuser with the thumbscrew
on the drawtube. Insert a 1.25" diagonal into the adapter,
and secure the diagonal by tightening the thumbscrew on the
1.25" eyepiece adapter. Insert your 1.25" eyepiece into the
diagonal and secure it in place with the thumbscrew(s) on the
diagonal.
Getting Started
The Express 80mm comes fully assembled from the factory.
The telescope’s optics have been installed and aligned, so
you should not have to make any adjustments to them. Open
the box and inspect the contents to make sure all of the items
in the parts list are present.
Please keep the original shipping box. In the unlikely event
you should need to ship the telescope back to Orion for warranty repair service, you should use the original packaging.
The Express 80mm is a very versatile instrument, designed
for terrestrial and astronomical use both visually and
photographically. To customize the telescope for your specific usage, you will need to add specific optional accessories
including eyepieces, diagonal, finder scope, and a tripod or
mount (Figure 2).
Eyepiece
Diagonal
Mounting the Telescope on a Tripod or Telescope
Mount
The Express 80mm can be mounted on any standard camera
tripod that has a 1/4"-20 stud. The stud threads into one of
the two threaded holes in the mounting block on the underside of the telescope’s tube. Choose the hole whose position
provides the best balance for your particular configuration of
telescope and accessories. Alternatively, the telescope can
be attached to an equatorial mount equipped with a 1/4"-20
adapter. An equatorial mount is desirable for astronomical
viewing because it allows easy manual tracking of celestial
objects as the Earth rotates. Also, the setting circles on the
mount enable you to locate objects by their celestial coordinates (right ascension and declination), which can be found in
many observing books and star atlases.
Installing a Diagonal and Eyepiece
The Express 80mm can be used with 2" or 1.25" eyepieces and accessories. To use a 2" diagonal and eyepieces,
loosen the thumbscrew on the end of the focuser drawtube
Equatorial
mount
Figure 2. The Express 80mm with optional accessories.
WARNING: Never look directly at the Sun through
your telescope—even for an instant—without a
professionally made solar filter that completely
covers the front of the instrument, or permanent
eye damage could result. Young children should use
this telescope only with adult supervision.
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Focusing
The Express 80mm is equipped with a precision Crayford
focuser. When you first look in the eyepiece, the image you see
may be fuzzy, or out of focus. If so, gently turn one of the large
focusing wheels with your fingers until the image becomes
sharp. You will have to readjust the focus when aiming at
subjects of varying distances, or after changing eyepieces.
Make sure the focus lock thumbscrew on the underside of the
focuser is loosened before focusing. After focusing, you can
tighten it to lock the telescope’s focus into place.
You may need to adjust the tensioning of the focuser drawtube. This can become especially important if you are using
heavy accessories or have a camera attached to the telescope. Make this adjustment by either tightening or loosening
the focus tensioning set screw on the underside of the focuser
assembly. Use either a 2.5mm or 3/32" hex key to make this
adjustment.
For convenience and ease of use, you can rotate the entire
focuser assembly on the tube of the Express 80mm. Loosen
the focuser rotation thumbscrew (see Figure 1) to change the
orientation of the focuser. You may also need to back off the
three set screws that attach the focuser to the telescope; use
a small flat-head screwdriver to unthread each set screw a
couple of turns. Be sure to re-tighten the thumbscrew once
you have rotated the focuser assembly to the desired position.
Depending on the combinations of eyepieces, diagonals,
adapters and cameras you are using, an extension tube may
be useful in achieving focus for very close subjects. Optional
extension tubes are available in both 1.25 and 2" diameters.
Do You Wear Eyeglasses?
If you wear eyeglasses, you may be able to keep them on
while you observe, if your eyepieces have enough “eye relief”
to allow you to see the whole field of view. You can find out by
looking through the eyepiece first with your glasses on and
then with them off, and see if the glasses restrict the view
to only a portion of the full field. If they do, you can easily
observe with your glasses off by just refocusing the telescope
the needed amount.
Every telescope has a useful limit of power of about 45x60x per inch of aperture, which is 140x-190x for the Express
80mm. Claims of higher power by some telescope manufacturers are a misleading advertising gimmick and should be
dismissed. Keep in mind that at higher powers, an image will
always be dimmer and less sharp (this is a fundamental law
of optics). Chromatic aberration appears as color fringing
around bright objects, and becomes more severe with higher
magnifications. The steadiness of the air (the “seeing”) can
also limit how much magnification an image can tolerate.
Always start viewing with your lowest-power (longest focal
length) eyepiece in the telescope. After you have located and
looked at the object with it, you can try switching to a higherpower eyepiece to ferret out more detail. If the image you see
is not crisp and steady, reduce the magnification by switching
to a longer-focal-length eyepiece. As a general rule, a small
but well-resolved image will show more detail and provide a
more enjoyable view than a dim and fuzzy, over-magnified
image.
You will also find it useful to be able to calculate the true field
of view for a given eyepiece in your telescope. This will help
you select the optimal eyepiece for a specific object. To calculate the true field of view, find the apparent view in your
eyepiece’s specifications. Then divide this by the magnification provided by the eyepiece in your telescope. For example,
a 40mm eyepiece with a 62° apparent field of view will provide
a magnification of 12x in the Express 80mm. Dividing 62° by
12 results in a true field of view of just over 5°.
Installing a Finder Scope
While you can aim the Express 80mm fairly easily by just starting with a low-power eyepiece, many people prefer the added
ease and convenience that comes from using an optional
finder scope. The Express 80mm has threaded holes in the
focuser assembly that allow attachment of an optional dovetail holder that will accept a variety of finder scopes (Figure 3).
Consult the Orion catalog or www.OrionTelescopes.com for
the dovetail holder and available finder scopes.
Calculating Magnification (Power)
It is desirable to have a range of eyepieces of different focal
lengths, to allow viewing over a range of magnifications. To
calculate the magnification, or power, of a telescope, simply
divide the focal length of the telescope by the focal length of
the eyepiece:
Magnification = Telescope F.L. ÷ Eyepiece F.L.
For example, the Express 80mm, which has a focal length of
480mm, used in combination with a 10mm eyepiece, yields a
power of
480 ÷ 10 = 48x.
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Dovetail holder
Figure 3. An optional dovetail holder connects to the Express
80mm, and allows attachment of a finder scope. Remove the two
set screws from the threaded holes before installing the dovetail
holder.
Extendable Lens Shade
The lens shade on the Express 80mm extends and retracts
along the telescope tube. When viewing through the telescope, make sure the lens shade is extended to block stray
light from entering the telescope, which reduces image contrast. 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 horizontal (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 subject 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 necessary. 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° correctimage diagonal. The 90° star diagonal is more comfortable for
looking up at the higher angles common in astronomical viewing. 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 backwards (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 manually “track” the motion of celestial objects in the night sky with
just one slow-motion control cable. Furthermore, with an equatorial 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 planetarium software package can come in handy for helping locate
interesting objects among the dizzying multitude of stars overhead. 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 targets 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 nebulae, 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-contrast, 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 distances 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 constellation 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.
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Solar System Observing
Though optimized for wide-field astronomical viewing, you can
use higher-power eyepieces with the Express 80mm to enjoy
exciting views of the Moon, Sun, and planets.
A. The Moon
The Moon, with its rocky, cratered surface, is one of the easiest
and most interesting subjects to observe with your telescope.
The myriad craters, rilles, and jagged mountain formations
offer endless fascination. The best time to observe surface features on the Moon is during a partial phase, that is, when the
Moon is not full. During partial phases, shadows cast by crater
walls and mountain peaks along the border between the dark
and light portions of the lunar disk highlight the surface relief.
Use an optional Moon filter to dim the Moon when it is very
bright. It simply threads onto the bottom of the eyepiece (you
must first remove the eyepiece to attach the filter). You’ll find
the Moon filter improves viewing comfort, and helps bring out
the subtle features in the lunar surface.
B. The Sun
You can change your telescope into a daytime Sun viewer
by installing an optional full-aperture solar filter over the front
opening of the Express 80mm. 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.
C. The Planets
The planets don’t stay put like stars do (planets don’t have
fixed R.A. and Dec. coordinates), so you will have to refer to
Sky Calendar at our website, www.OrionTelescopes.com, to
a desktop planetarium software package, to charts published
monthly in Astronomy, Sky & Telescope, or other astronomy ref-
erences to locate them. First find the planet using a low-power
eyepiece. Then raise the magnification as high as atmospheric seeing will allow. Venus and Mercury will show distinct and
changing phases when viewed through the Express 80mm.
(Caution: do not attempt to view any planet when it is near the
Sun in the sky.) Mars’ apparent size varies greatly depending
on its orbital position relative to Earth; during close approaches you will be able to observe its polar ice caps and dark rocky
patches on its surface. Jupiter will display its distinctive cloud
bands and the constantly changing positions of its four largest
moons. Saturn’s system of rings and largest moon Titan will be
clearly visible. The planets Uranus and Neptune are too distant
to show significant detail even in very large telescopes, but
you will be able to pick them out from the background stars by
their amazing blue-green color.
nebulae will often be much more visible using narrowband nebula filters, even in dark skies. A range of color filters will bring
out different subtle details in the planets. Moon filters provide
a more comfortable view of the dazzlingly bright Moon in its
fuller phases, and can also be useful when viewing Venus.
These filters are designed to screw into the threads at the bottom of your eyepieces, and come in both 1.25" and 2" sizes.
The 1.25" eyepiece adapter included with the Express 80mm
is threaded to accept 2" filters. This is a great convenience
when using the 1.25" eyepiece adapter in a 2” diagonal, as you
no longer have to detach and re-attach the filter every time you
change 1.25" eyepieces.
Photography with the
Express 80mm
With an optional camera adapter, the Express 80mm becomes
a 480mm f/6 telephoto lens for a single-lens reflex camera with
a removable lens. This is known as the prime focus method of
photography through your telescope. A 2" camera adapter will
provide the most even field illumination across your camera’s
field of view. The camera adapter is secured directly to the
focuser drawtube in place of the diagonal. You will also need
a T-ring for your particular camera model. The T-ring attaches
to your particular camera model and threads onto the camera
adapter (Figure 4).
Many popular cameras do not have removable lenses. You
can get excellent pictures through your telescope with these
cameras if you use the afocal method. This method essentially
replaces your eye with the camera and requires the use of an
adapter, such as the Orion SteadyPix, to hold the camera up
to the eyepiece.
Whichever method of photography you use, be sure to secure
your camera and camera adapter to the telescope by tightening the thumbscrew on the focuser drawtube, or your camera
could fall to the ground! Use the telescope’s focuser to focus
the image. Tighten the focus lock thumbscrew on the underside of the telescope’s focuser to make sure the camera does
not slip out of focus. You will want to consider using a remote
shutter release instead of the manual shutter release on the
camera; touching the camera can vibrate the system and blur
the resulting photographic image. Also, be sure to use a solid
tripod.
2" Camera adapter
Using Filters
A wide variety of filters can greatly enhance your views through
the Express 80mm. For galaxies, star clusters, star fields and
dark nebulae, a broad-band light pollution reduction filter can
be a great benefit in skies brightened by city lights. Emission
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T-ring
Figure 4. To connect a 35mm SLR camera to the Express 80mm,
you’ll need an optional camera adapter and T-ring.
Care & Maintenance
Give your telescope reasonable care and it will last a lifetime.
Store it indoors or in a dry garage. The included padded soft
carry case is an excellent container for storing and transporting your Express 80mm. Do not leave the telescope outside
except when using it. The optical tube is aluminum and has a
smooth anodized surface that resists scratches and smudges.
If a scratch does appear on the tube, it will not harm the telescope. Smudges on the tube can be wiped off with standard
household cleaning fluid.
Any quality optical lens tissue and cleaning fluid specifically
designed for multi-coated optics can be used to clean the
telescope’s objective lens. Never use regular glass cleaner or
cleaning fluid designed for eyeglasses. Before cleaning with
fluid and tissue, however, blow any loose particles off the lens
with a blower bulb or compressed air, or lightly brush the lens
with a soft camel hair brush. Apply some cleaning fluid to a
tissue, never directly on the optics. Wipe the lens gently, then
remove any excess fluid with a fresh lens tissue. Oily fingerprints and smudges may be removed using this method. Use
caution; rubbing too hard may scratch the lens. Clean only a
small area at a time, using a fresh lens tissue on each area.
Specifications
Objective lens: Achromatic, fully multi-coated
Aperture: 80mm
Focal length: 480mm
Focal ratio: f/6
Focuser: Crayford, 2", 1.25" adapter included
Optical tube length: 338mm
Weight of optical tube assembly: 5.5 lbs.
Mounting block: Accepts 1/4"-20 threaded studs
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One-Year Limited Warranty
This Orion Express 80mm Refractor Telescope is warranted against defects in materials or workmanship for a period of one year from the date of purchase. This warranty is for the benefit of the original
retail purchaser only. During this warranty period Orion Telescopes & Binoculars will repair or replace, at
Orion’s option, any warranted instrument that proves to be defective, provided it is returned postage paid
to: Orion Warranty Repair, 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. For further warranty service information,
contact: Customer Service Department, Orion Telescopes & Binoculars, P. O. Box 1815, Santa Cruz, CA
95061; (800)-676-1343.
Orion Telescopes & Binoculars
Post Office Box 1815, Santa Cruz, CA 95061
Customer Support Help Line (800)‑676‑1343 • Day or Evening
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