Orion 9895 User manual

INSTRUCTION MANUAL
IN 221 Rev. B 03/09
Orion 80mm f/7.5 ED Refractor
#9895 Optical Tube Assembly
Congratulations on your purchase of an Orion 80mm f/7.5 ED
refractor optical tube. Your 80mm f/7.5 ED has been designed
with high quality optics and excellent mechanical construction.
The ED glass in the objective lens means you’ll enjoy images
with far less color distortion than those seen in a standard
refractor, and the smooth Crayford focuser will make getting
sharp images a breeze. These instructions will help you set up
and use your telescope tube.
Getting Started
The 80mm f/7.5 ED comes fully assembled from the factory.
The telescope’s optics have been installed and collimated, so
you should not have to make any adjustments to them.
Please keep the original shipping box! In the unlikely event
you should need to ship the telescope back to Orion for war-
ranty repair service, you should use the original packaging.
The box also makes a very good container for storing the tele-
scope when it is not in use.
Attaching the Refractor to a Tripod or Mount
The 80mm f/7.5 ED can be attached to a tripod or mount by
the use of the 1/4"-20 mounting block. The 1/4"-20 shaft of a
sturdy camera tripod will thread into the hole on the mounting
block on the underside of the optical tube.
Optional tube rings can also be used to mount the scope to a
telescope mount. Tube rings with an inner diameter of 100mm
(3.9"), such as Orion item #7371, are needed. If you are using
tube rings, you should rst attach them to your telescope
mount and then lay the optical tube in the tube rings.
Use of Optional Eyepieces, Diagonal, and Finder
Scope
The 80mm ED does not come with a nder scope, diagonal or
eyepieces in order to grant the user the greatest versatility in
customizing the instrument to suit their tastes. However, cer-
tain rules for using accessories still apply.
Any Orion nder scope with a dovetail bracket can be used
with the 80mm f/7.5 ED. Simply unthread the thumbscrew on
the dovetail mount (Figure) and insert the assembled nder
scope and dovetail bracket. Retighten the thumbscrew. Finder
scopes that do not use a dovetail bracket will need to be
attached by other means.
The 80mm ED can use almost any 1.25" diagonal and eye-
piece. Please note that the telescope will not come to focus
without the use of a diagonal or extension tube. To install
a diagonal, unthread the thumbscrew on the 1.25" adapter
(Figure) until it is ush with the interior of the adapter. Insert
the diagonal or extension tube and secure it with the thumb-
Figure. The 80mm f/7.5 ED Refractor optical tube assembly
Dew/Glare shield
Machined aluminum lens cell
Finder scope dovetail mount
2" Crayford focuser
1.25" Eyepiece
adapter
Crayford focuser tension
thumbscrew
Focus wheel (2)
1/4"-20 mounting block
Corporate Offices: 89 Hangar Way, Watsonville CA 95076 - USA
Toll Free USA & Canada: [phone]
International: [phone]
Customer Support: [email protected]
Copyright © 2021 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

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screw. Then insert the eyepiece into the diagonal or extension
tube and secure it with the thumbscrew.
Use of 2" Eyepieces and Diagonals
A feature of the 80mm ED is its ability to also use 2" barrel-
diameter eyepieces and diagonals. At low magnications, 2"
eyepieces can give a wider eld of view than standard 1.25"
eyepieces. This is especially desirable for observing deep-sky
objects, as many of them appear quite large, but faint. As with
1.25" eyepieces, the 80mm ED will not reach focus with the
2" eyepieces unless a 2" diagonal or extension tube is used.
To use 2" eyepieces, simply loosen the two large thumb-
screws on the 2" adapter (Figure). Once these thumbscrews
are loosened, the entire back end of the focuser, including any
1.25" diagonal and eyepiece that may be attached, comes off,
exposing the 2" diameter focuser drawtube. Now, insert your
2" diagonal into the drawtube and secure with the two thumb-
screws loosened previously. Insert a 2" eyepiece into the diag-
onal, secure it in place with the thumbscrew on the diagonal,
and you’re ready to observe.
Note About the 2" Crayford Focuser
The 80mm ED comes equipped with a Crayford focuser. The
Crayford design allows for smooth, precise focusing without
any image shift that typical rack-and-pinion designs expe-
rience. If you nd that the focus wheels are too tight or too
loose, you can make adjustments to the focuser tension by
using the focuser tension thumbscrew located on the bottom
of the optical tube, between the focus wheels. Make adjust-
ments to this thumbscrew until the focuser motion feels com-
fortable. Please note that you must have at least some tension
applied to the focuser drawtube or else it will not move when
you turn the focus wheels.
Calculating Magnification (Power)
It is desirable to have a range of eyepieces of different focal
lengths, to allow viewing over a range of magnications. To
calculate the magnication, or power, of a telescope, simply
divide the focal length of the telescope by the focal length of
the eyepiece:
Telescope F.L. ÷ Eyepiece F.L. = Magnication
For example, the 80mm ED, which has a focal length of
600mm, used in combination with a 25mm eyepiece, yields
a power of
600 ÷ 25 = 24x.
Every telescope has a useful limit of power of about 45x-60x
per inch of aperture. Claims of higher power by some tele-
scope manufacturers are a misleading advertising gimmick
and should be dismissed. Keep in mind that at higher pow-
ers, an image will always be dimmer and less sharp (this is a
fundamental law of optics). The steadiness of the air (the “see-
ing”) will limit how much magnication 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 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 magnication 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, overmagnied image.
Note About Chromatic Aberration
Chromatic aberration literally means color distortion.
Whenever light passes through one material to another, light
of different wavelengths (color) is 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
a slightly different amount when passing through a lens. This
results in each color of light reaching precise focus at a slightly
different point, which reduces image sharpness.
The 80mm ED is designed to minimize chromatic aberration.
The objective lens comprises two individual lens elements,
one of which is made of “ED” (Extra-low Dispersion) glass,
a special type of glass that has superior refractive properties
compared to normal types of glass. The use of this ED glass
minimizes the amount of chromatic aberration, resulting in a
cleaner, sharper image compared to that in standard achro-
matic telescopes.
Photography with the 80mm ED Refractor
With an optional camera adapter, the 80mm f/7.5 ED becomes
a 600mm f/7.5 telephoto lens for a single-lens reex camera.
For long-distance terrestrial or astronomical photography, you
need only a T-ring for your particular camera model. The T-ring
attaches to your camera and threads onto the 80mm ED’s
focuser drawtube, coupling the camera body to the telescope.
Use the camera’s viewnder to frame the picture. Use the tele-
scope’s focuser to focus the image. Tighten the focuser ten-
sion thumbscrew to make sure the camera does not slip out
of focus.
You may want to consider using a remote shutter release
instead of the shutter release on the camera. Touching the
camera can vibrate the system and blur the resulting photo-
graphic image. Also, be sure to use a solid tripod.
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 it indoors or in a dry garage.
Do not leave the telescope outside except when using it. The
optical tube is aluminum and has a smooth painted surface
that should resist 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 clean-
ers such as Windex or Formula 409.
Any quality optical lens tissue and cleaning uid specically
designed for multi-coated optics can be used to clean the tele-
scope’s objective lens as well as the lenses of eyepieces and
nder scopes. Never use regular glass cleaner or cleaning
uid designed for eyeglasses. Before cleaning with uid and
tissue, however, blow any loose particles off the lens with a
blower bulb or compressed air, or lightly brush the lens with

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a soft camel hair brush. Apply some cleaning uid to a tissue,
never directly on the optics. Wipe the lens gently in a circular
motion, then remove any excess uid with a fresh lens tissue.
Oily ngerprints 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.
Specifications
Optical tube: Seamless aluminum
Objective lens diameter: 80mm (3.1")
Objective lens: Achromatic, rear element made of ED glass,
air-spaced
Objective lens coating: Fully multi-coated
Lens cell: Machined aluminum
Focal length: 600mm
Focal ratio: f/7.5
Focuser: Crayford, accepts 1.25" or 2" accessories and
camera T-Ring
Mounting: 1/4"-20 mounting block, optional tube rings
Weight: 5 lbs. 11 oz.
Length: 23.5"
Corporate Offices: 89 Hangar Way, Watsonville CA 95076 - USA
Toll Free USA & Canada: [phone]
International: [phone]
Customer Support: [email protected]
Copyright © 2021 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.