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Finder scope compatibility
Adding an optional finder scope to the EON 110 is easy. The
focuser is equipped with two pre-tapped M4-.7 holes on the
focuser to accommodate an optional Orion dovetail finder
scope shoe (#7214), which is compatible with any Orion finder
scope or "red dot" reflex sight, or the Orion Dual Finder Scope
bracket.
4. Operating the
EON 110mm
The EON 110mm is a versatile telescope designed for both
high-performance imaging and wide-field visual pursuits. Its
fast f/6 focal ratio and ample 110mm ED optics make it an
especially powerful instrument for imaging with CCD or DSLR
cameras.
Now that you have become familiar with the different features
and functions of the telescope, you are ready to begin using
your new telescope outside under a starry sky. Be sure to allow
the telescope to equilibrate to the outdoor temperature for at
least ½ hour before using it; this ensures the best image quality.
connecting the EON 110mm to a
telescope Mount
The EON 110mm ED f/6.0 refractor comes with a pair of stur-
dy, hinged tube rings. On the top and bottom bosses of the
rings are multiple 1/4"-20 tapped holes for attachment of dove-
tail plates. Four 1/4"-20 socket head cap screws are included
with the rings. You will need one dovetail plate on the bottom to
couple the telescope to your mount's dovetail saddle. You may
also want to mount another plate on top for attachment of a
guide scope for imaging.
Balancing the telescope can be done by moving the telescope
forward or backward within the tube rings, or by sliding the dove-
tail mounting plate forward or backward in your mount's saddle.
Observing with the EON 110
To observer with the EON 110 you will need either a 1.25" or 2"
diagonal and an eyepiece, each sold separately. Because the
optics are made with high-quality ED glass, the eyepieces you
choose should also have excellent, fully multi-coated optics to
utilize the full performance of the telescope. 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:
Telescope Focal Length (mm)
Eyepiece Focal Length (mm)
If outside viewing conditions are ideal, a telescope with good
optics can achieve a magnification of about 60x per inch, or
2.4x per millimeter, of aperture. Keep in mind that at higher
powers, an image will always be dimmer and less sharp (this
is a fundamental law of optics). In most cases the steadiness
of the air (the "seeing") will limit how much magnification the
scope can tolerate, rather than the telescope itself.
= Magnification
Always start viewing with your lowest-power (longest focal
length) eyepiece in the telescope. After you have located and
observed the object with it, you can try switching to a higher-
power eyepiece to ferret out more detail, if atmospheric con-
ditions permit. 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.
imaging with the EON 110
Given its high-quality, apochromatic optics and fast f/6.0 focal
ratio, the EON 110 excels for astrophotography with a CCD
or DSLR camera. To attach a DSLR camera, all you will need
is the appropriate T-ring for the make and model of your cam-
era, a 2" prime focus camera adapter, and a 2" extension tube
(available from Orion). Simply attach the T-ring to the camera
body and thread the 2" prime focus camera adapter into the
T-ring. Insert the barrel of the camera adapter into the 2" exten-
sion tube, then install the 2" extension tube in the 2" accessory
collar of the focuser and secure it with the thumbscrews.
Most CCD cameras will have a 1.25" or 2" barrel ready to
attach directly to your telescope like an eyepiece or diagonal.
No adapter is required, simply insert the barrel of the CCD
camera into the 1.25" adapter or 2" accessory collar and
secure the camera with the thumbscrew(s). Depending on
your camera, you may need to use an extension tube for your
particular imaging setup. Any imaging accessory, such as a
color filter wheel, increases the amount of inward focus travel
required.
For optically fast refractors such as the EON 110, an option-
al field flattener is a desirable accessory to compensate for
inherent field curvature. The flattener will ensure tight, sharp
stars out to the edge of your imaging sensor, and is highly
recommended if you are using a camera with an APS-C size
sensor or larger. The Orion Field Flattener for Short Refractors
(#8893) is a perfect match for this instrument.
Before attaching any extra imaging accessory, try reaching
focus first with the camera directly attached to the focuser,
then see if you have enough inward focus travel left for extra
accessories.
The hybrid-drive, 2.7" dual-speed focuser of the EON 110 is
capable of handling the weight of your CCD or DSLR cam-
era and accessories, up to 17.6 lbs. (8Kg). The drawtube ten-
sion is set at the factory and should not need adjusting. After
installing your camera equipment onto the focuser, check the
focuser for any slippage. If it slips under the weight of the cam-
era, you may need to add more tension to the focuser. Do this
by lightly tightening the drawtube tension setscrew (Figure 3).
Note About chromatic Aberration
Chromatic aberration literally means color distortion. Whenever
light passes through one material to another,
different wavelengths (color) are bent by different amounts.
This is a problem that plagues refractor-type telescopes, since
light passes through both air and glass to form an image. Most
astronomical objects emit a spectrum comprised of many dif-
ferent wavelengths of light, so each wavelength will be bent by
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