Focusing the Telescope
The ShortTube 80 OTA is outfitted with a 1.25" rack and pin-
ion focuser. Once you have installed your equipment use the
black plastic knobs to adjust the focus of your visual or pho-
tographic accessories. This will rack the drawtube in and out,
changing the focal distance of the light path. To ensure the
sharpest focus go slightly past your perceived focus point and
then reverse directions until you have a sharp focus.
Visual Back
The ShortTube 80 OTA is equipped with a 1.25" visual back.
You can attach 1.25" accessories by loosening the thumb-
screw and inserting the barrel until it stops, then secure it in
place by re-tightening the thumbscrew.
The male threads at the back of the tube are specified as
T-threads. Any camera accessory with a T-thread such as
many commercially available CCD and CMOS imagers and
T-rings for SLR/DSLR camera bodies can be coupled to the
Short Tube 80 by threading them on directly. This method is
often preferred because it provides added stability for your
accessories.
Care and Maintenance
If you give your ShortTube 80 reasonable care, it will last a
lifetime. Store it in a clean, dry, dust-free place, safe from rapid
changes in temperature and humidity. Keep the dust cover on
the front of the telescope when it is not in use. The ShortTube
80 OTA requires very little mechanical maintenance. The opti-
cal tube is aluminum and has a smooth painted finish that is
fairly scratch-resistant. If a scratch does appear on the tube,
it will not harm the telescope. Smudges on the tube can be
wiped off with a soft cloth and a household cleaner such as
Formula 409.
Cleaning Lenses
Any quality optical lens cleaning tissue and optical lens clean-
ing fluid specifically designed for multi-coated optics can be
used to clean the telescope’s objective lens. Never use regu-
lar glass cleaner or cleaning fluid designed for eyeglasses.
Before cleaning with fluid and tissue, blow any loose particles
off the lens with a blower bulb or compressed air. Then 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.
Specifications
Objective lens: Achromatic doublet, air-spaced
Objective lens coatings: Fully multi-coated
Aperture: 80mm
Focal length: 400mm
Focal ratio: f/5
Focuser: Rack-and-pinion, 1.25", accepts
camera T-ring
Optical tube length: 15"
Weight of optical
tube assembly: 3 lbs., 7 oz.
One-Year Limited Warranty
The Orion ShortTube 80 OTA 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. Proof of purchase (such as a copy of the original receipt)
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, con-
Orion Telescopes & Binoculars
89 Hangar Way, Watsonville CA 95076
Customer Support Help Line (800) 676-1343 • Day or Evening
