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Video and WebCamera Types

Video Camera :


Advantages :
The video camera can be connected to a video monitor or TV set and so enabling many people to see live images through the telescope simultaneously . This is especially interesting for public work , but the live image is also interesting even if you are alone with the telescope .
It is also posssible to record on videotape/cassette for a later review and capture to computer, or for capture of the images directly to a computer . This is , of course , of great interest for imaging .
The video camera takes 25 or 30 images per second , making it possible to select the best of a long string of images . In view of the poor (turbulent) seeing most amateur astronmers experience this is the most important aspect of video astronomy imaging .
No guiding needed , due to the short exposures .
Small field of view , good for planetary imaging
With a portable recorder (could be a camcorder with recording facility) the setup is well suited for work in the field .

Disadvantages :
Since the video camera takes 25 or 30 images per second the exposure time is too short (less than 1/25th or 1/30th second) to capture faint objects like nebulae .
NOTE : Newer video cameras like the Stellacams can integrate the images
Small field of view , not well suited for extended objects
Interlaced type images
This is all I could think of for now .

Webcam :


Advantages:
The video camera takes 25 or 30 images per second , making it possible to select the best of a long string of images . In view of the poor (turbulent) seeing most amateur astronmers experience this is the most important aspect of video astronomy imaging .
No guiding needed , due to the short exposures .
Small field of view , good for planetary imaging
Progressive scan, i.e no problems with interlaced images

Disadvantages :
Since the video camera takes 25 or 30 images per second the exposure time is too short (less than 1/25th or 1/30th second) to capture faint objects like nebulae .
NOTE : Some people have come up with  long exposure modifications for some brands of webcams
Small field of view , not well suited for extended objects
Computer needed for image capture


Conclusion :
The video camera or the webcam is well suited for imaging the Solar System , i.e. Sun (don't forget the filters , or you WILL end up with a useless piece of junk in stead of a camera) , the Moon , bright planets , Saturn is the limit .
Some video cameras have features called "Nightshot" or "Low Lux" . This can extend the camera's limits to show somewhat fainter objects , like small constellations , bright novae and star clusters . I believe the only nebula that will ever show up on images made with video cameras will be M42 - The Great Orion Nebula . Some people have used the video camera to image meteors and meteor impacts on the Moon .
Because of the often terrible seeing where I observe these pages will deal mainly with video astronomy imaging .

For really high resolution imaging, planets, moon etc the webcam is likely to be the winner when it comes to image quality, and the video camera for showing live pictures on a TV, as well as recording video.

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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