Celestron C8-NGT Manuale Utente
41
6. Find a suitable guide star in the telescope eyepiece field of view. This is relatively easy since you can
search a wide area without affecting the area covered by your camera lens. If you do not have an
illuminated cross hair eyepiece for guiding, simply defocus your guide star until it fills most of the field of
view. This makes it easy to detect any drift.
illuminated cross hair eyepiece for guiding, simply defocus your guide star until it fills most of the field of
view. This makes it easy to detect any drift.
7. Release the shutter using a cable release.
8. Monitor your guide star for the duration of the exposure making the neccessary corrections needed to keep
the star centered.
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Short exposure prime focus photography is the best way to begin recording celestial objects. It is done with
the camera attached to the telescope without an eyepiece or camera lens in place. To attach your camera,
you need the T-adapter and a T-Ring for your specific camera (i.e., Minolta, Nikon, Pentax, etc.). The
C8-N and C10-N focuser have a built-in T-adapter and are ready to accept a 35mm camera body. The T-
Ring replaces the 35mm SLR camera’s normal lens. Prime focus photography allows you to capture the
entire solar disk (if using the proper filter) as well as the entire lunar disk. To attach your camera to your
telescope:
the camera attached to the telescope without an eyepiece or camera lens in place. To attach your camera,
you need the T-adapter and a T-Ring for your specific camera (i.e., Minolta, Nikon, Pentax, etc.). The
C8-N and C10-N focuser have a built-in T-adapter and are ready to accept a 35mm camera body. The T-
Ring replaces the 35mm SLR camera’s normal lens. Prime focus photography allows you to capture the
entire solar disk (if using the proper filter) as well as the entire lunar disk. To attach your camera to your
telescope:
1 Remove the eyepiece from the 1
1
/
4
" eyepiece holder.
2 Unthread the 1
1
/
4
" eyepiece holder from the focuser assembly. This will expose the male thread of the built-
in T-adapter.
3 Thread the T-ring onto the exposed T-adapter threads.
4 Mount your camera body onto the T-Ring the same as you would any other lens.
With your camera attached to the telescope, you are ready for prime focus photography. Start with an easy
object like the Moon. Here’s how to do it:
1. Load your camera with film that has a moderate-to-fast speed (i.e., ISO rating). Faster films are more
desirable when the Moon is a crescent. When the Moon is near full, and at its brightest, slower films are
more desirable. Here are some film recommendations:
• T-Max 100
• T-Max 400
• Any 100 to 400 ISO color slide film
• Fuji Super HG 400
more desirable. Here are some film recommendations:
• T-Max 100
• T-Max 400
• Any 100 to 400 ISO color slide film
• Fuji Super HG 400
2. Center the Moon in the field of your telescope.
3. Focus the telescope by turning the focus knob until the image is sharp.
4. Set the shutter speed to the appropriate setting (see table 7-1).
5. Trip the shutter using a cable release.
6. Advance the film and repeat the process.