Orion 9975 - Manual

instruction Manual
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100mm f/9 ED refractor
#9975 Optical Tube Assembly
C ongratulations on your purchase of an Orion 100mm f/9 ED
refractor optical tube. Your 100mm f/9 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 100mm f/9 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
Optional tube rings should be used to attach the scope to a
telescope mount. Tube rings with an inner diameter of 100mm
(3.9"), such as Orion item #7371, are needed. When using
tube rings, you should first 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 100mm ED does not come with a finder scope, diagonal
or eyepieces in order to grant the user the greatest versatil-
ity in customizing the instrument to suit their tastes. However,
certain rules for using accessories still apply.
Any Orion finder scope with a dovetail bracket can be used
with the 100mm f/9 ED. Simply unthread the thumbscrew on
the dovetail mount (Figure 1) and insert the assembled finder
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 100mm ED can use almost any 1.25" diagonal and eye-
piece. To install a diagonal, unthread the thumbscrew on the
1.25" adapter (Figure 1) until it is flush with the interior of the
adapter. Insert the diagonal and secure it with the thumbscrew.
Then insert the eyepiece into the diagonal and secure it with
the thumbscrew.
use of 2" Eyepieces and Diagonals
A feature of the 100mm ED is its ability to also use 2" barrel-
diameter eyepieces and diagonals. At low magnifications, 2"
eyepieces can give a wider field 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. Please
note that the 100mm ED will not reach focus with the 2" eye-
pieces unless a 2" diagonal or extension tube is used.
Figure 1. The 100mm f/9 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)
IN 247 Rev B 02/09