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Figure 6.
To use a CCD camera with the 8" f/4.0 Newtonian
Astrograph, the camera must have a 1.25" or 2" nosepiece, which
is inserted into the appropriate accessory holder in the focuser.
An external camera adapter with T-threads could be used in lieu of
the nosepiece.
Imaging with the 8" f/4.0 Newtonian Astrograph
This instrument has fast f/4.0 parabolic optics, which pro-
duce bright images and allow fairly short exposure times.
Fast optics also inherently produce some coma, or distor-
tion of star images toward the periphery of the field of view.
Therefore, to achieve the best possible images, we recom-
mend using a coma corrector (sold separately). The coma
corrector is attached to the focuser drawtube in front of the
camera body. 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. Check Orion's website
for compatible coma correctors.
Attaching a CCD Camera
Most CCD cameras have a 1.25" or 2" barrel, or nosepiece,
that allows attachment directly to your telescope's focuser
like an eyepiece. No adapter is required. Simply insert the
nosepiece of the CCD camera (Figure 6) into the 1.25" or 2"
eyepiece holder and secure the camera with the thumbscrew
lock.
If your CCD imager does not include a compatible nose-
piece, or if you wish to utilize the camera's T-threads, a Zero-
Profile Prime Focus Camera Adapter is required (available
from Orion). The zero-profile adapter has male T-threads that
couple to the female T-threads of your camera. The adapter's
2" barrel is inserted and secured in the focuser just like a 2"
eyepiece.
Attaching a DSLR Camera
To attach a DSLR camera, you will need the appropriate T-ring
for the make and model of your camera and a Zero-Profile
Prime Focus Camera Adapter. Simply attach the T-ring to the
camera body and thread the Zero-Profile Camera Adapter
onto the threads of 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 (Figure 7).
6
1.25" nosepiece
Figure 7.
the particular camera model and a T-adapter, such as the Orion
Zero-Profile Prime Focus Camera Adapter, which fits into the 2"
accessory collar.
Figure 8.
the focuser drawtube. It is needed to reach focus for visual use of the
8" f/4.0 Newtonian Astrograph.
Visual Observing with the 8" f/4.0
Newtonian Astrograph
To achieve focus with a telescope eyepiece, you will likely have
to use the included 35mm-long extension adapter (Figure 8).
Just insert it into the 2" collar on the focuser and tighten the
two thumbscrews to secure the extension adapter in place.
Then insert either a 2" eyepiece or a 1.25" eyepiece (using
the 1.25" adapter) into the 35mm extension adapter.
Collimating the Optics
(Aligning the Mirrors)
Collimating is the process of adjusting the mirrors so they are
aligned with one another. Your telescope's optics were aligned
at the factory, and should not need much adjustment unless
the telescope was handled roughly in transit. Accurate mir-
ror alignment is important to ensure the peak performance of
your telescope, so it should be checked regularly. Collimating
Zero-profile
camera adapter
(not visible)
Attachment of a DSLR camera requires a T-ring for
The 35mm extension adapter adds 35mm of length to
T-ring
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