Orion 10269 User manual

Orion®6" f/4 Newtonian
Astrograph
#10269
IN 575 Rev. A 09/16
INSTRUCTION MANUAL
Corporate Offices: 89 Hangar Way, Watsonville CA 95076 - USA
Toll Free USA & Canada: [phone]
International: [phone]
Customer Support: [email protected]
Copyright © 2020 Orion Telescopes & Binoculars.All Rights Reserved. No part of this product instruction or any of its contents
may be reproduced, copied, modied or adapted, without the prior written consent of Orion Telescopes & Binoculars.
AN EMPLOYEE-OWNED COMPANY

2
Figure 1. Included components of the 6" f/4 Newtonian Astrograph. (Allen wrench not shown.)
Tube rings
Screws (2)
Optical tube
8X50 nder scope
and bracket
Dovetail nder
scope base
Dovetail bar
Front
cap
2" extension adapter
Table of Contents
Introduction 2
Parts List 3
Preparing the Telescope for Use 3
Placing the Telescope in the Tube Rings" 3
2" Dual-Speed Crayford Focuser 3
Fine Focus 3
Attaching the Finder Scope 3
Aligning the Finder Scope 3
Focusing the Finder Scope 4
Operating the Telescope 4
Attaching a DSLR Camera 4
Attaching a CCD Camera 4
Observing with the 6” f/4 Newtonian Astrograph 5
Collimating the Optics (Aligning the Mirrors) 5
The Primary Mirror Center Mark 5
Preparing the Telescope for Collimation 5
Aligning the Secondary Mirror 6
Aligning the Primary Mirror 6
Star-Testing the Telescope 6
Care & Maintenance 7
Specications 8
WARNING: Never look directly at the Sun with the
naked eye or with a telescope – unless you have
a proper solar lter installed over the front of the
telescope! Otherwise, permanent, irreversible eye
damage may result.
Introduction
Congratulations on your purchase of the Orion 6" f/4
Newtonian Astrograph! This compact, short-focal-
length reector telescope features high-quality para-
bolic optics, a 2" dual-speed Crayford focuser, and
excellent mechanical construction. It is optimized for
astrophotography with DSLR and astronomical CCD
imaging cameras, but can also provide excellent visual
views with optional eyepieces.
This instruction manual will help you to set up and
properly use your telescope. Please read it through
completely before attempting to use the scope and its
included accessories.

3
Parts List
• Optical tube assembly
•Optical tube dust cap
•8x50 crosshair nder scope
•Finder scope dovetail bracket with rubber O-ring
•Pair of hinged tube rings
•Dovetail mounting bar
•Screws for tube ring attachment (x2)
•2" to 1.25” eyepiece holder
•2" extension adapter
•Allen wrench
•Starry Night Special Edition digital download
We recommend keeping the original shipping box and packag-
ing material. In the unlikely event you should need to ship the
telescope back to Orion for warranty repair service, you should
use the original packaging to ensure the telescope stays intact
during shipping. Take a moment to inspect the telescope and
all of its parts. Before proceeding with the instructions, refer to
Figure 1 to familiarize yourself with some of the features and
components of the telescope.
Preparing the Telescope
for Use
Placing the Telescope in the Tube Rings"
The 6" f/4 Newtonian Astrograph comes with a pair of hinged,
felt-lined tube rings to hold the optical tube assembly (OTA)
on a mount. Each ring has a at boss on opposing sides. Both
bosses have an M6 threaded hole in the center. Attach the
tube rings to the dovetail mounting bar with the two socket
head cap screws provided, using the included Allen wrench to
tighten them (Figure 2).
Then place the OTA in the open tube rings and clamp the rings
closed. Not that the tube rings will need to be positioned so
that the front ring is next to the focuser, for proper balance.You
can rotate the tube inside the rings prior to tightening the tube
ring clamp knobs to achieve the desired eyepiece or camera
orientation.
The telescope has an extended length of optical tube in front
of the focuser, compared to a standard Newtonian, to prevent
any possibility of incoming light impinging directly on the sec-
ondary mirror or entering the focuser drawtube. This ensures
the best possible contrast when observing and photographing
faint celestial objects.
2" Dual-Speed Crayford Focuser
The 6" f/4 Newtonian Astrograph features an all-metal, 2" dual-
speed (10:1) Crayford-type focuser (Figure 3) with a linear
bearing rail for added stability. A steel reinforcing plate inside
the optical tube just under the focuser provides extra rigidity,
minimizing “exing” of the focuser housing on the tube due to
the weight and moment arm of your imaging camera.
If the drawtube slips under the weight of your imaging system
or heavy visual accessories, tighten the drawtube tensioning
thumbscrew on the underside of the focuser as needed. On
the other hand if the focuser motion seems too stiff, loosen the
drawtube tensioning thumbscrew a bit. Once focus is reached,
you can lock the drawtube in place by tightening the focus lock
knob on the top side of the focuser. The focuser drawtube has
a 2" collar on the end of it, with two thumbscrews, for attach-
ment of 2" accessories. The telescope comes with a 1.25" eye-
piece holder inserted into the 2" collar that can be used with
1.25" eyepieces or accessories.
Fine Focus
The dual-speed, linear bearing Crayford focuser features both
coarse and ne focusing wheels. The two large, silver-colored
wheels are for coarse focusing. The small black wheel next
to the large focus wheel on the right allows ne-focus adjust-
ment at a gear ratio of 10:1, meaning ten turns of the ne focus
wheel equals one turn of the large focus wheel. Use the large
focus wheels to achieve rough focus on your target object, then
use the ne focus wheel to home in on the exact focus point.
Attaching the Finder Scope
The included 8x50 crosshair nder scope is useful for locating
objects in the sky and centering them in the main telescope’s
eld of view. To install it, rst remove the O-ring from the brack-
et and place it over the body of the nder scope until it seats
in the narrow groove near the middle of the nder or is just
behind it. Unthread the two black nylon alignment screws on
the bracket until the screw ends are ush with the inside sur-
face of the bracket. Slide the eyepiece end (narrow end) of the
nder scope into the end of the bracket’s cylinder opposite the
alignment screws while pulling the chrome, spring-loaded ten-
sioning pin on the bracket with your ngers (Figure 4a). Push
the nder scope through the bracket until the O-ring seats just
inside the front opening. Release the tensioner and tighten the
two black nylon screws a couple of turns each to secure the
nder scope in place. Now slide the foot of the nder scope
bracket into the dovetail base on the main telescope.You’ll rst
have to back out the thumbscrew lock on the dovetail base a
few turns to allow the bracket to slide in. Once the bracket is
inserted, tighten the thumbscrew lock (Figure 4b).
Aligning the Finder Scope
The nder scope and the main telescope must be aligned so
they point to exactly the same spot in the sky. Alignment is
easiest to do in daylight. First, insert an eyepiece (a crosshair
eyepiece is best) into the eyepiece holder in the telescope’s
focuser. Point the telescope at an object such as the top of a
telephone pole or a street sign that is at least a quarter mile
away. Move the telescope so the target object appears in the
very center of the eld of view when you look into the eyepiece.
Now look through the nder scope. Is the object centered in
the nder scope’s eld of view? If not, hopefully it will be visible
somewhere in the eld of view, so that only a minor adjustment
of the nder scope’s two alignment screws will be needed to
center it. Otherwise you’ll have to make coarser adjustments to
redirect the aim of the nder scope.

4
Once the target object is centered on the crosshairs of the
nder scope, look again in the telescope’s eyepiece and see
if it is still centered there as well. If it isn’t, repeat the entire
process, making sure not to move the telescope while adjust-
ing the alignment of the nder scope. When the target object is
centered on the crosshairs of the nder scope and in the tele-
scope’s eyepiece, the nder scope is aligned and ready to be
used for locating objects. The nder scope alignment should
be checked before every imaging or observing session. This
can easily be done at night, before viewing through the tele-
scope. Choose any bright star or planet, center the object in
the telescope eyepiece, and then adjust the bracket’s align-
ment screws until the star or planet is also centered on the
nder’s crosshairs.
Focusing the Finder Scope
If the image in the nder scope appears out of focus, you will
need to refocus the nder scope for your vision. First, loosen
the knurled lock ring located behind the objective lens cell on
the body of the nder scope (see Figure 4a). Back the lock
ring off by a few turns. Then refocus the nder scope on a
distant object by rotating the objective lens cell clockwise or
counterclockwise. Once the image appears sharp, retighten
the knurled lock ring behind the objective lens cell. The nder
scope’s focus should not need to be adjusted again.
Operating the Telescope
Your Orion 6" f/4 Newtonian Astrograph is designed primarily
for astro-imaging, but it makes a ne visual instrument as well
(more about that later).
For imaging applications, the telescope is optimized for use
with an APS-C or smaller size sensor. This instrument’s para-
bolic primary mirror has a focal length of 610mm and a fast f/4
focal ratio. It produces bright images and allows short expo-
Figure 2. Attaching the dovetail mounting bar to the tube rings.
Insert screw
here
Figure 3. The aluminum 2” dual-speed linear bearing focuser.
Compression
ring
Fine focus
wheel
2" collar
Coarse focus
wheels
1.25"
Adapter
Drawtube
tensioning
thumbscrew
Focus
lock
knob
sure times. Fast optics also inherently produce some coma,
or distortion of star images toward the periphery of the eld
of view. Therefore, to achieve the best possible images, we
highly recommend use of a coma corrector (sold separately)
designed for use with f/4 Newtonians, or for a range of focal
ratios that includes f/4. Many common coma correctors have
a 2" diameter housing and T-threads for attachment to a cam-
era. Typically, the coma corrector is attached to the front of
the camera body via its T-threads (for DSLRs, to a compat-
ible T-ring), then inserted into the 2" accessory collar of the
focuser drawtube. Use of a coma corrector will allow you to
utilize the entire imaging area of your camera without the need
to crop the edges of your astro-images due to optical distor-
tion. Check Orion’s website for compatible coma correctors.
Attaching a DSLR Camera
To attach a DSLR camera, you will need the appropriate T-ring
for the make and model of your camera. If using a coma cor-
rector (highly recommended), thread it into the T-ring attached
to your DSLR camera body, then insert the coma corrector
housing into the focuser through the 2" accessory collar and
tighten the two locking thumbscrews on the collar to secure
the camera in place. If you do not plan to use a coma correc-
tor, then you will need a prime focus camera adapter (avail-
able from Orion). Simply attach the T-ring to the camera body
and thread the camera adapter into the T-ring. Then insert the
barrel of the camera adapter into the focuser’s 2" accessory
collar and secure it with the two thumbscrew locks.
Attaching a CCD Camera
The 6" f/4 Newtonian Astrograph is equipped to accept CCD/
CMOS astronomical cameras with either a 2" or 1.25" nose-
piece, or a 2" coma corrector in place of the nosepiece, which
slides directly into the telescope’s focuser like an eyepiece.
The 2" nosepiece is secured with the two thumbscrew locks.
If your CCD imager does not include a compatible 2" nose-

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piece, or if you wish to utilize the camera’s T-threads without
a coma corrector, a zero-prole prime focus camera adapter
is required (available from Orion). The zero-prole adapter
has male T-threads that couple to the female T-threads of your
camera. Note that, depending on your CCD camera’s speci-
cations, you may need to insert the 2" extension adapter in
front of the camera in order to achieve focus.
You may also need to add T-thread spacer rings between the
coma corrector and the CCD camera, to achieve the neces-
sary critical distance between the coma corrector’s rear lens
element and the camera’s imaging sensor. Consult the manu-
als for your camera and the coma corrector to determine the
spacing needed.
Observing with the 6” f/4 Newtonian Astrograph
The 6" f/4 Newtonian Astrograph is optimized for photographic
imaging, but it can also be used for visual observing of celes-
tial objects. (Because the eld of view in a Newtonian reector
is rotated from right-side-up, this type of telescope is not rec-
ommended for terrestrial observing.) For visual use, we rec-
ommend using high-quality eyepieces to take full advantage of
the instrument’s excellent optical quality.
To achieve focus with most eyepieces for visual use, you will
need to install the included 2" extension adapter in the focuser,
then insert either a 2" or 1.25" eyepiece into the extension
adapter. (If using a 1.25" eyepiece, you will need to insert the
1.25" adapter into the 2" extension adapter.) If you use a coma
corrector that works for visual use (some work only for photog-
raphy), you may not need the extension adapter to reach focus
with your eyepiece(s).
Collimating the Optics
(Aligning the Mirrors)
Collimating is the process of adjusting the mirrors so they are
aligned with one another. Precise collimation of the optics is
especially critical for fast Newtonian optics such as in the f/4
astrograph. If the mirrors are even slightly misaligned, image
quality will suffer.Your telescope’s optics were collimated at the
factory, but it doesn’t take much to knock them slightly out of
alignment. So you should check the collimation before every
observing or imaging session, to make sure it is dead on. The
process of collimation is a relatively easy and can be done in
daylight or darkness.
To check collimation, remove the eyepiece and look down the
focuser drawtube, keeping your eye centered in the drawtube.
You should see a reection of the primary mirror (i.e., the big
mirror at the bottom of the tube) and inside it a smaller reec-
tion of the secondary mirror (i.e., the small diagonally oriented
mirror under the focuser). The reected image of the primary
and secondary mirrors should be centered to one another, with
your eye at the very center of the view. If the reections do not
look aligned, some adjustment will be needed, so you should
proceed with the collimation procedure.
We strongly recommend the use of a laser collimating tool
such as the Orion LaserMate Deluxe to aid in collimating the
optics. A laser collimator will ensure a more precise collimation
than you can achieve just by “eyeballing” it. With fast optics like
those of the 6" f/4, getting a very precise collimation is critical
for obtaining the sharpest, crispest images, so a laser collima-
tor is a worthwhile (and small) investment.
The Primary Mirror Center Mark
You’ll notice that the primary mirror of the 6" f/4.0 Newtonian
Astrograph has a tiny ring (sticker) marking its center. This
“center mark” allows you to achieve a very precise collimation
of the primary mirror; you don’t have to guess where the exact
center of the mirror is.
NOTE: The center ring sticker need not ever be removed from
the primary mirror. Because it lies directly in the shadow of the
secondary mirror, its presence in no way adversely affects the
optical performance of the telescope or the image quality. That
might seem counterintuitive, but it’s true!
Preparing the Telescope for Collimation
Once you get the hang of collimating, you will be able to do it
quickly even in the dark. For now, it is best to collimate in day-
Knurled ring
Spring pin
Figure 4. (a) Insert the nder scope into the bracket, then (b) install the bracket foot into the dovetail nder scope base and secure it with
the thumbscrew lock.
Thumbscrew
lock
Dovetail nder
scope base
O-ring Thumbscrews
b.
a.

6
light, preferably in a brightly lit room and aimed at a white wall.
It is recommended that the telescope tube be oriented hori-
zontally. This will prevent any parts from the secondary mirror
from falling down onto the primary mirror and causing damage
if something comes loose while you are making adjustments.
Aligning the Secondary Mirror
To adjust the secondary mirror collimation, you will need a
small Phillips screwdriver. If the entire primary mirror reection
is not visible in the secondary mirror, as in Figure 5b, you will
need to adjust the tilt of the secondary mirror. First, loosen one
of the three alignment set screws by, say, a half turn, and then
lightly tighten the other two to take up the slack (Figure 6). Do
not loosen the center screw during this process. The goal is to
center the primary mirror reection in the secondary mirror, as
in Figure 5c. Did the primary mirror reection move closer to
being centered in the secondary mirror? If so, continue loosen-
ing the same setscrew and tightening the other two. But if the
primary mirror reection moved in a direction other than toward
the center, then you should try loosening a different setscrew
and tightening the other two. It takes some trial and error with
loosening one setscrew and tightening the others to get the
primary mirror reection centered in the secondary mirror.
When it is centered, you’re done adjusting the secondary mir-
ror. Don’t worry that the reection of the secondary mirror (the
small circle with the four spider vanes adjoining it and with
your eye’s reection inside it) is off-center, since that adjust-
ment is made when aligning the primary mirror in the next step.
Aligning the Primary Mirror
The primary mirror will need adjustment if, as in Figure 5c, the
reection of the primary mirror is centered in the secondary
mirror, but the reection of the secondary mirror is off-center.
The tilt of the primary mirror is adjusted with three large colli-
mation knobs on the rear end of the optical tube (bottom of the
primary mirror cell), shown in Figure 7. The thinner knobs are
lock knobs, which secure the mirror in place once the correct
tilt has been achieved.
To adjust the primary mirror’s tilt, rst loosen all three lock
knobs a couple of counterclockwise turns each. Now, while
looking into the focuser, turn one of the collimation knobs
(which are spring loaded) a half turn or so in either direction
and see if the secondary mirror reection moves closer to the
center of the primary. If it does, great, keep going until you get
it as close as you can. If it doesn’t, try turning the collimation
knob in the opposite direction. If turning the one knob does
not seem to do the trick, try adjusting one of the other large
knobs. Again, it will take some trial-and-error using all three
large collimation knobs to properly align the primary mirror.
Over time you will get the feel for which collimation screws to
turn to move the image in a given direction.
When you have the secondary mirror reection centered as
much as possible in the primary mirror’s reection, your prima-
ry mirror is collimated. Now lightly tighten the three lock knobs
to secure the primary mirror in place.
The view down the focuser should now resemble Figure 5a.
A simple star test will indicate how well the telescope optics
are collimated.
Figure 5. Collimating the optics. (a) When the mirrors are properly
aligned, the view down the focuser drawtube should look like this.
(b) Here, the secondary mirror is centered under the focuser, but
it needs to be adjusted (tilted) so that the entire primary mirror is
visible. (c) The secondary mirror is correctly aligned, but the primary
mirror still needs adjustment.
Center
ring on
primary
mirror
For a more complete description of the collimation proce-
dure, see our article Collimation of a Newtonian Reflector
Telescope in the support materials for this telescope on
our website.
Star-Testing the Telescope
When it is dark, point the telescope at a bright star and accu-
rately center it in the eyepiece’s eld of view. (To achieve focus
with an eyepiece, you will likely have to use the included 35mm
extension adapter, as described previously.) Slowly de-focus
the image with the focusing knob. If the telescope is correct-
ly collimated, the expanding disk should be a perfect circle
(Figure 8). If the image is unsymmetrical, the scope is out of
collimation. The dark shadow cast by the secondary mirror
should appear in the very center of the out-of-focus circle, like
the hole in a donut. If the “hole” appears off-center, the tele-
scope is out of collimation.
If you try the star test and the bright star you have selected is
not accurately centered in the eyepiece, the optics will always
appear out of collimation, even though they may be perfectly
aligned. It is critical to keep the star centered, so over time you
a.
b. c.

7
will need to make slight corrections to the telescope’s posi-
tion in order to account for the sky’s apparent motion. Point
the telescope at Polaris (the North Star) if you do not have a
mount that tracks.
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 dust cap
on the eyepiece opening. Store the telescope indoors or in a
dry garage. Do not leave the telescope outside except when
using it. The optical tube is made from rolled steel and has a
smooth enamel surface. If a scratch appears on the tube, it will
not harm the telescope. Smudges on the tube can be wiped off
with standard household cleaners such as Windex or Formula
409.
In general, your telescope’s mirrors will only need to be cleaned
very infrequently, if ever. Covering the front opening of the tele-
scope with the dust cover when it is not in use will prevent dust
from accumulating on the mirrors. Keeping the dust cap on the
focuser’s 1.25" opening is also a good idea. Improper cleaning
can scratch the mirror coatings, so the fewer times you have
to clean the mirrors, the better. Small specks of dust or ecks
of paint have virtually no effect on the visual or imaging perfor-
mance of the telescope, so leave them be!
You should not have to remove the secondary mirror from the
telescope to lightly clean it. Just reach in carefully and brush
the surface lightly with a camel hair brush or blow off dust with
a photographer’s blower bulb. Do not use “canned air” on any
telescope optics as the propellants can leave residue and
stains on the mirror.
Do not attempt to remove the primary mirror cell from the tele-
scope tube.There are small nuts on the inside end of the small
screws that attach the mirror cell to the tube. They will come
off if the screws are loosened and are impossible to get back
on without removing the entire secondary mirror support! If
you believe the primary mirror needs cleaning, call Orion Tech
Support for further direction.
Figure 6. Adjust the secondary mirror tilt with the three Phillips
screws on the secondary mirror holder. Always start by loosening one
screw before lightly tightening one or both of the others.
Figure 7. The larger, spring-loaded collimation knobs are used to
adjust the primary mirror tilt, while the thinner knobs lock the mirror
in place. Loosen each lock knobs a couple turn before adjusting the
collimation knobs.
Secondary mirror
alignment screws
Figure 8. A star test will determine if the telescope’s optics are
properly collimated. A defocused view of a bright star through the
eyepiece should appear as illustrated on the right if the optics are
perfectly collimated. If the circle is unsymmetrical, as illustrated on
the left, the optics need alignment.
Out of collimation Collimated
Lock knobs
Collimation
knobs

8
Specifications
Optical conguration: Newtonian reector
Aperture: 150mm
Focal length: 610mm
Focal ratio: f/4
Primary mirror: BK7 glass, parabolic gure
Mirror coatings: Enhanced aluminum (94% reectivity) with SiO2 overcoat
Secondary mirror minor axis: 62.5mm
Backfocus distance: 77.1mm
Focuser: Dual-speed (10:1) 2" linear bearing Crayford, with 1.25" adapter
Optical tube: Rolled steel, gloss black enamel nish
Tube rings: Included, hinged, felt-lined
Finder Scope: 8x50, with dovetail bracket
2" Extension adapter: 35mm extension length
Weight: 12.7 lbs. (5.75 kg) – including nder scope, tube rings, and dovetail mounting bar
Length: 22.5" (580mm)
Corporate Offices: 89 Hangar Way, Watsonville CA 95076 - USA
Toll Free USA & Canada: [phone]
International: [phone]
Customer Support: [email protected]
Copyright © 2020 Orion Telescopes & Binoculars.All Rights Reserved. No part of this product instruction or any of its contents
may be reproduced, copied, modied or adapted, without the prior written consent of Orion Telescopes & Binoculars.
AN EMPLOYEE-OWNED COMPANY
One-Year Limited Warranty
This Orion product is warranted against defects in materials or workmanship for a peri-
od of one year from the date of purchase. This warranty is for the benet 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 defec-
tive, provided it is returned postage paid. Proof of purchase (such as a copy of the origi-
nal 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 modied, nor does it apply to normal wear and tear. This warranty gives
you specic 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.