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Video and Webcam -
CCD -
Digital Cameras (compact or DSLR
Photographic Film -
PrimeFocus and Eyepiece Projection -
Afocal Imaging -
Piggyback and Camera Direct -
Filter Use
Prime Focus Imaging
In prime focus imaging the optical path contains the fewest possible
elements . Ideally it consists of a single mirror or lens . In practise
a second mirror is usually added to the first mirror ,as in SCT or
Newtonian telescopes . Often a Barlow lens is added to the path in
order to increase the magnoification as is usual for visual
observations as well . The optical system projects the image on the
CCD-chip or the photographic film . Prime focus imaging provides for
the same magnification , or more precisely , field of view (FOV) given
the same optical path . The camera is fixed to the telescope with a
camera adapter or , in some cases it is mounted in place pf an eyepiece
using an eyepiece adapter .
The advantage of using this technique is the easily reproducable
mechanical arrangement providing for more reproducible results .
Compared to the afocal method the prime focus technique has less
problems since the camera optics are often of a lower quality than we
would like for astronomical use .
Prime focus imaging has until now been my primary method of
astroimaging .
Eyepiece Projection
This uses a camera adapter with an eyepiece mounted in front of the
imaging surface . In other respects the technique is like prime focus
imaging , however , much higher magnification is possible - provided
the aperture of the telescope allows it .
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Last update 21 January 2006 by Jan Andersen.
Background image : Video image of the Pleiades
Top caption : Lunar Eclipse 21-01-2000