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7. Install the four screw and nut pairs using the wrench or pliers
and the included hex key. Tighten the screws firmly.
Note: SkyQuest XT8 Classic Dobsonian telescopes purchased
prior to 2007 will require modification to accept this focuser.
If you do not have an 8" or 10" Orion Newtonian reflector,
you will need to modify your tube so the focuser will fit. This
will require drilling four holes into the tube for the mounting
screws. Use a 3/16" drill bit to do this. Use the base of the
focuser as a template when drilling these holes. You may also
need to cut a larger hole (approximately 2.5" diameter) in the
telescope for the bottom of the focuser. Be careful not to cut
your fingers on any sharp tube edges when attempting to do
this. Keep in mind that the minimum focus height for the 2"
Crayford focuser is approximately 43mm, so if your eyepieces
reach focus closer to the tube than this, additional modifica-
tions to the telescope may be required.
The focuser can be rotated, should the need arise. This
requires a 1.5mm hex key (not included). To reposition the
focuser, loosen the four small socket-head set-screws that are
located within the base. Rotate the focuser to the preferred
position and carefully tighten the four set screws with the
1.5mm hex key. Be sure to keep the focuser flat against the
base to ensure proper alignment.
Usage
Using the 2" dual-speed low-profile Crayford focuser is very
straightforward. Place your 2" eyepiece in the focuser draw-
tube, and secure it in place with the thumbscrew. Imaging
cameras should generally utilize a 2" camera adapter when
used with the focuser. Insert the camera adapter the same
way as a 2" eyepiece. To focus, simply rotate one of the focus
wheels.
The large focus lock thumbscrew near the focusing shaft (see
Figure 1) locks the drawtube into position once focus has
been achieved. This is especially useful when using a camera
or heavy eyepiece in the focuser. Be sure this thumbscrew is
loosened when focusing.
The socket head set screw above the focus lock thumbscrew
(see Figure 1) adjusts drawtube focusing tension. If a heavy
eyepiece causes the drawtube to move inward by itself (draw-
tube tension too loose), or the focus wheels are difficult to turn
(drawtube tension too tight), then you will want to adjust this
set screw. This requires the 2.5mm hex key.
In addition to the nominal focus travel of 24mm, the extend-
able drawtube adds up to 44mm of focus travel yielding a total
focus range of 68mm. To extend the drawtube, loosen the
drawtube extension thumbscrew and gently pull the drawtube
upwards to the preferred position. Tighten the drawtube exten-
sion thumbscrew to lock the drawtube in place. The extendable
drawtube is a welcome feature when switching between an
eyepiece and camera, as no external extension tubes are
required.
The 2" Dual-Speed Low-Profile Crayford focuser provides
the most focus range for accessories that require extra in-
travel. With a minimum focus height of 49mm, this focuser is
an excellent choice for any astrophotographic system. The
strong machined aluminum construction supports heavy 2"
eyepieces as well as heavy camera bodies. The smooth focus
motion and fine-focus knob allow precision adjustments for
critical focusing of eyepieces and cameras.
In addition to the nominal focus travel of 24mm, the extendable
drawtube adds up to 44mm of focus travel yielding a total focus
range of 68mm. To extend the drawtube, loosen the drawtube
extension thumbscrew and gently pull the drawtube upwards to
the preferred position. Tighten the drawtube extension thumb-
screw to lock the drawtube in place. The extendable drawtube
is a welcome feature when switching between an eyepiece and
camera, as no external extension tubes are required.
Fine Focus
The focuser features dual speed adjustment with the fine focus
wheel. This small black wheel located on the side of the right-
hand focus wheel allows precise focus adjustment at a ratio of
11:1, meaning one turn of the focus wheel equals eleven turns
of the fine focus wheel.
Use the focus wheels to achieve rough focus on your target
object, then use the fine focus wheel to coax out even more
detail. You'll be amazed at the amount of detail fine focus adjust-
ments allow you to view on targets such as the lunar surface,
planets, double stars, as well as other celestial objects.
The 1.25" Eyepiece Adapter
In order to use a 1.25" eyepiece in the focuser, you must first
install the 1.25" eyepiece adapter. Place this adapter into the
drawtube like a 2" eyepiece, and loosely secure it with the
thumbscrew. Insert a 1.25" eyepiece into the adapter, and
secure the eyepiece by further tightening the thumbscrew.
Tightening the thumbscrew compresses a ring around the
1.25" eyepiece adapter, which in turn secures and precisely
centers the 1.25" eyepiece.
Specifications
Focuser design:
Crayford, accepts 2" eyepieces
and 1.25" eyepieces with included
adapter.
Minimum focus height: 43mm
Focus travel:
24mm, 68mm with 2" drawtube
extended
Other features:
Focus lock, drawtube focusing
tension adjustments, fine focus wheel
(11:1) compression fit 1.25" eyepiece
adapter
One-Year Limited Warranty
This Orion 2" Dual-Speed Low-Profile Crayford Focuser for Newtonian
Reflectors 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. If the product is not registered, proof of
purchase (such as a copy of the original invoice) 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, contact: Customer Service Department,
Orion Telescopes & Binoculars, 89 Hangar Way, Watsonville, CA
95076; (800)-676-1343.
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