Orion EON 110mm ED f/6.0 User manual

Orion®EON™110mm ED f/6.0
Apochromatic Refractor
#10031
IN 496 Rev.D 11/18
INSTRUCTION MANUAL
Customer Support:
www.OrionTelescopes.com/contactus
Corporate Offices:
89 Hangar Way, Watsonville CA 95076 - USA
Providing Exceptional Consumer Optical Products Since 1975
Copyright © 2018 Orion Telescopes & Binoculars
All Rights Reserved. No part of this product instruction or any of its contents may be reproduced, copied, modified or adapted,
without the prior written consent of Orion Telescopes & Binoculars.

Table of Contents
Parts List ................................................................................... 2
Getting Started ......................................................................... 2
Features and Functions ........................................................... 3
Operating the EON 110mm ED ............................................... 4
Care & Maintenance ................................................................ 5
Specifications ........................................................................... 7
Parts List
• EON 110mm ED f/6.0 optical tube assembly
• Aluminum objective cap
• 1.25" twist-tight adapter
• Tube rings (pair)
• Hard carrying case
• 2.5mm hex key
Getting Started
The EON 110mm ED apochromatic refractor comes fully
assembled from the factory. The telescope’s optics have been
assembled and precisely collimated at the factory, so they
should not require any adjustments. Please keep the original
shipping box. In the unlikely event that you need to ship the
telescope back to Orion for warranty repair service, you should
use the original packaging.
Congratulations on your purchase of an Orion EON 110mm ED f/6.0 Apochromatic Refractor! Your telescope has been designed
with high quality precision ED optics and superior mechanical construction. The 2.7” hybrid-design, dual-speed (11:1) Crayford
focuser with linear bearings will rigidly support heavy imaging or visual equipment loads and provide smooth, backlash-free focus-
ing. The extra-low dispersion, or “ED,” optics offer outstanding color correction. These instructions will help you set up and use your
telescope.
2
Figure 1. Features and components of the EON 110 ED F/6.0
Apochromatic Refractor
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.
Finder scope base
Tube rings
1.25" twist-
tight collar
2" twist-tight
collar Fine focus knob
Coarse focus knobs (x2)
2.7" hybrid-design focuser
Retractable dew shield

Features and Functions
The EON 110 ED apochromatic refractor has premium features
designed to maximize the performance of the scope and its
convenience of use. Please refer to Figure 1 to become famil-
iar with the telescope’s features.
“Extra-Low Dispersion” (ED) Doublet Optics
The EON 110 ED utilizes high-end doublet optics designed to
minimize chromatic aberration. The objective lens assembly
comprises two individual lenses, the crown (front) element,
and flint (rear) element. The flint glass element is made from
FPL-51 ED glass, made by Ohara of Japan. The “ED” stands
for “Extra-Low Dispersion”. The use of this ED glass minimizes
chromatic dispersion, or the amount of chromatic aberration,
resulting in a much sharper image free of color fringing. Critical
stellar or planetary observations become more accurate with
this color correction since the focused images are free of “false”
color halos around the object.
Retractable Dew Shield
The dew shield of the EON 110 ED is retractable, allowing the
telescope to become more compact for storage. With the dew
shield extended, the scope is 26.75"long; with the dew shield
retracted, the length reduces to 21.75". The dew shield’s pri-
mary purpose is to inhibit dew (water condensation) from form-
ing on the lens during cold and humid nights. The dew shield is
also useful for reducing glare from unwanted outside lights. To
extend the dew shield, simply pull it forward until it stops.
Dual-Speed 2.7"Hybrid-Design Linear Bearing
Focuser
Focusing the EON 110 ED is truly a joy, thanks to the all-
machined, 2.7"hybrid-drive linear bearing focuser (Figure
2). And for imaging, where a focuser’s rigidity to support one’s
imaging equipment without flexure or slippage is critical, this
focuser makes the grade. The hybrid design rack-and-pinion
linear bearing focuser provides exceptionally smooth, back-
lash-free focus motion. The helical gear drive and 8 ball bearing
linear-bearing system enables the focuser to support up to a
hefty 8kg (17.6 lbs.) of payload -- such as a large format CCD
camera, filter wheel, and other accessories. The patented focus
lock mechanism locks the drawtube in two directions, providing
a much more rigid lock than the single-point locking mechanism
found on most focusers. The lock knob is located on the under-
side of the focuser (Figure 3).
The dual-speed (11:1) focusing mechanism will keep your tar-
get object crisp and sharp. For quick focusing, the two large
focus knobs provide a coarse focus. For more precise focus-
ing, as needed for applications such as high-power planetary
observing and imaging with a CCD or digital camera, the small-
er focus knob on the right side (Figure 2) offers an 11:1 fine
focus adjustment (11 turns of the fine focus knob equals one
turn of the coarse focus knob).
If you find that the focus adjustment is too hard to turn or if
the drawtube slips under the weight of your eyepiece or cam-
era, you can make adjustments to the focuser tension by using
the focuser tension setscrew located on the bottom side of the
focuser (Figure 3). Make adjustments to this setscrew until
the focuser motion feels smooth and holds in place when you
have obtained focus. It may be necessary to make adjustments
when the weight of your accessories changes significantly.
Twist-Tight Accessory Collars
The latest release of the EON 110mm ED features a 2"twist-
tight collar and a 1.25"twist-tight adapter (Figure 4). The
twist-tight mechanism replaces and is superior to conventional
collars that utilize a thumbscrew to secure accessories to the
focuser. Thumbscrews can sometimes fall out and get lost,
and are harder to grip in the cold when wearing gloves. The
twist-tight mechanism provides an extremely secure attach-
ment with just a twist of the large knurled collar. Both collars
have a non-marring internal compression ring for securing a
3
Figure 2. The 2.7” dual-speed, hybrid-drive focuser has two
rotatable components.
Figure 3. The underside of the focuser features a focus lock knob
and drawtube tension setscrew.
2" twist-tight
accessory collar
Slotted screw (x3)
Slotted screw (x3)
Focus lock knob
Drawtube tension
setscrew
Tapered
collar
1.25" twist-tight accessory
collar (1.25" adapter)
Rotation ring for 2"
accessory collar
Fine focus knob
Coarse focus knob
Rotation thumbscrew locks

diagonal, field flattener, camera adapter, or other accessories.
To insert an accessory into the collar, first twist the collar coun-
terclockwise to widen the internal compression ring, then insert
your 2"accessory into the collar (or your 1.25"accessory into
the 1.25"collar). Then just twist the collar clockwise until it is
tight. The 1.25"adapter has a tapered barrel, which provides an
even more secure fit into the 2"collar, such that even a slight,
inadvertent loosening of the 2"collar will not result in the 1.25"
adapter slipping out.
Engraved Millimeter Scale on Focuser Drawtube
The drawtube of the EON 110 ED’s focuser features a laser-
engraved millimeter scale on top (Figure 5), which aids in pro-
viding repeatable focus. When precise focus is achieved, noting
the value on the scale where the drawtube meets the focuser
housing will allow you to return to approximately the same point,
such as when focusing the same a camera in subsequent imag-
ing sessions. Using the scale can save time compared to find-
ing the focusing point “from scratch.”
Focuser Rotation
The focuser on the EON 110 ED has two rotatable components.
The entire focuser can be rotated just behind the tapered collar
where the focuser attaches to the optical tube (see Figure 2).
The second point of rotation is the rotation ring for 2"accessory
collar behind the focus knobs. Both of the rotation mechanisms
have three recessed, slotted screws that must be slightly loos-
ened to permit rotation, as well as a thumbscrew lock.
Why two points of rotation? Rotating the entire focuser will re-
orient the focus knobs to a position that may be more desirable,
depending on your mount setup and what you’re observing or
imaging. For instance, this feature can allow you to keep the
focus knobs parallel to the ground no matter how your telescope
is positioned. Rotating the rotation ring for the 2"accessory col-
lar, additionally, may be useful for framing a target object for
imaging.
To rotate the focuser, loosen the rotation lock thumbscrew
(Figure 2) a turn or so counterclockwise. Gently rotate the fo-
cuser to the desired orientation, then lock it in place by turning
the lock thumbscrew clockwise. If you find the focuser is difficult
to rotate, you may have to very slightly loosen the three slotted
screws around the focuser with a small flat-blade screwdriver
(not included). If, on the other hand, you feel too much “play” in
the focuser when the thumbscrew is loosened, you may need to
tighten the slotted screws a bit. You want the focuser to be able
to rotate but without play.
Reaching Focus
Your EON 110mm ED apochromatic refractor must be used with
either a diagonal or extension tube in order for an eyepiece to
reach focus. In most cases, you will be using a 90° star diagonal
for visual use with an eyepiece. A camera will also likely require
a 2"extension adapter to reach focus. An optional 2"field flat-
tener designed for short-focal-length refractors, such as the
Orion Field Flattener for Short Refractors (#8893), can be used
instead of an extension adapter.
Finder Scope Compatibility
Adding an optional finder scope to the EON 110 ED is easy.
The focuser is equipped with a dovetail finder scope base (see
Figure 1) that accepts any Orion finder scope or reflex sight as
well as the Orion Dual Finder Scope bracket (#10145).
Operating the EON 110mm
ED
The EON 110mm ED 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
4
Figure 5. The engraved millimeter scale on the focuser aids in
quickly achieving repeatable focus.
Figure 4. New to this edition of the EON 110 ED are twist-tight 2”
accessory collar and 1.25” adapter with twist-tight collar.
1.25" adapter
Twist-tight collars

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 ED to a Telescope
Mount
The EON 110mm ED refractor comes with a pair of sturdy,
hinged tube rings. On the top and bottom bosses of the rings
are multiple M6-0.75 tapped holes for attachment of dovetail
plates. Four M6-0.75 socket head cap screws are included with
the rings. You will need one dovetail plate on the bottom to cou-
ple 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
dovetail mounting plate forward or backward in your mount’s
saddle.
Observing with the EON 110 ED
To observe with the EON 110 ED 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:
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.
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 ED
Given its high-quality, apochromatic optics and fast f/6.0 focal
ratio, the EON 110 ED 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"twist-tight
accessory collar of the focuser and rotate it clockwise to tighten.
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" twist-tight adapter or 2" twist-tight collar and rotate
it clockwise to tighten. 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 ED, an optional
field flattener is a desirable accessory to compensate for inher-
ent field curvature. The flattener will ensure tight, sharp stars
out to the edge of your imaging sensor, and is highly recom-
mended 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 acces-
sories.
The hybrid-drive, 2.7"dual-speed focuser of the EON 110 ED is
capable of handling the weight of your CCD or DSLR camera
and accessories, up to 17.6 lbs. (8Kg). The drawtube tension 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 camera, you may
need to add more tension to the focuser. Do this by lightly tight-
ening 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 wave-
lengths (color) are bent by different amounts. This is a prob-
lem that plagues refractor-type telescopes, since light passes
through both air and glass to form an image. Most astronomi-
cal objects emit a spectrum comprised of many different wave-
lengths of light, so each wavelength will be bent by a slightly dif-
ferent amount when passing through a lens. This results in each
color of light reaching precise focus at a slightly different point,
which will provide a soft image with a halo of unfocused color.
The EON 110's high quality ED optics are designed to minimize
chromatic aberration, resulting in a much sharper, more pleas-
ing view as compared to refractors that do not utilize ED glass.
Care & Maintenance
Give your telescope reasonable care and it will last a lifetime.
When not in use, keep its dust cover on as well as the small
plastic plug on the 1.25"adapter. Keep the telescope inside its
case when not in use (Figure 6). Store it indoors or in a dry
garage. Do not leave the telescope outside except when using
it. If a scratch appears on the tube, it will not harm the tele-
scope. Smudges on the tube can be wiped off with standard
household cleaners.
= Magnification
Telescope Focal Length (mm)
Eyepiece Focal Length (mm)
5

Dew
When you are ready to pack up your telescope at the end of
the night, avoid immediately storing it if you encountered heavy
dew and the telescope is damp. Instead, bring the telescope
inside and allow the moisture on the telescope to evaporate. If
dew forms on the objective lens, then leave the dust cover off
of the telescope until all the moisture has evaporated. Once the
telescope has completely dried out, place it back in its case.
Cleaning Optical Surfaces
In general, your telescope will only need to be cleaned on a very
minimal basis. Dust particles on the objective lens do not affect
the optical quality of your EON 110 ED. Loose dust can simply
be blown off with air, using a compressed air can or a photogra-
pher’s blower bulb. Any remaining dust is best left alone, unless
the build up is extreme. Fingerprints and water marks should be
cleaned from your telescope’s objective lens. Any quality opti-
cal lens tissue and cleaning fluid specifically designed for multi-
coated optics can be used to clean the telescope’s objective
lens as well as the lenses of your eyepieces and finder scope.
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 in a circular motion, 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. Never reuse tissues.
6
Figure 6. The EON 110 optical tube comes in a foam-fitted,
aluminum-clad carrying case.

Specifications
Optical tube: Seamless aluminum
Optics design: Air-spaced doublet
Lens cell: Machined aluminum
Lens glass: ED S-FPL51 and S-NBM51
Aperture: 110mm
Focal length: 660mm
F-ratio: 6.0
Lens coatings: Fully multi-coated (all air-to-glass surfaces multi-layer coated)
Tube baffles: Knife edge baffles (x3)
Tube length, dew shield retracted: 21.75"/ 552mm
Tube length, dew shield extended: 26.75"/ 679mm
Dew shield outer diameter: 5.32"/ 135.2mm
Weight: 11 lbs. 10.8 oz. (with tube rings attached)
Tube rings: Hinged, felt lining, three 1/4"-20 holes on upper and lower bosses
Focuser: 2.7" Hybrid drive, linear bearings with 8 ball bearings; 11:1 dual speed
Focuser weight capacity: 17.6 lbs. / 8kg
Drawtube travel: 3.74"/ 95mm
Rotatable focuser: Yes
Focus lock: Patented design, locks in two directions
Finder scope: Optional
Accessory collar: 2"twist-tight with self-centering brass compression ring
1.25"adapter: Included; twist-tight collar, brass compression ring, tapered barrel
Diagonal: Not included
Eyepiece: Not included
Field flattener: Optional
Case: Aluminum clad with die-cut foam interior; outer dimensions 28.25" x 9.25" x 9.75" / 718mm x 235mm x 247mm
7

Orion®Telescopes & Binoculars
Corporate Offices: 89 Hangar Way, Watsonville CA 95076 - USA. Customer Support: www.OrionTelescopes.com/contactus
Copyright © 2018 Orion Telescopes & Binoculars. All Rights Reserved. No part of this product instruction or any of its contents may be repro-
duced, copied, modified or adapted, without the prior written consent of Orion Telescopes & Binoculars.
One-Year Limited Warranty
This Orion product 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 war-
ranted instrument that proves to be defective, provided it is returned postage paid. Proof of purchase
(such as a copy of the original receipt) is required. This warranty is only valid in the country of purchase.
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. It is
not intended to remove or restrict your other legal rights under applicable local consumer law; your state
or national statutory consumer rights governing the sale of consumer goods remain fully applicable.
For further warranty information, please visit www.OrionTelescopes.com/warranty.
8