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Video and Webcam - CCD - Photographic Film - PrimeFocus and Eyepiece Projection - Afocal Imaging - Piggyback and Camera Direct - Filter Use
Using the camera without any extra optical aid ( apart from the built-in lens , telelens or teleconverter ) .
Camera direct is the easy way of astronomical imaging . Just place the camera on a tripod , point to the sky , and shoot , be it with a photographic or a video camera .
With a photographic 35mm camera and a 50mm focal length the exposure time should be limited to about 30 seconds if you want to image point-like stars . With longer focal lengths make sure you reduce the exposure time , or use some sort of tracking device . With the video camera this problem does not exist since the exposure time of the video camera is only 1/25th or 1/30th second .
The photo cameras are well suited to image constellations and star fields . Colours is no problem . Imaging small fields of view is of limited use with the short focal lengths and photo .
The standard video camera/camcorder is well suited to image Sun , Moon and ,of course , eclipses .
With video the shorter exposure times are to a certain extent compensated for by the better sensitivity of a CCD chip . In addition some modern video cameras/camcorders have features like "Low Lux" and "Nightshot" . Both allow the camera to use a longer exposure (about 8 times the standard video exposure) . In addition the "Nightshot" removes the infrared filter from the optical path and so increasing the sensivity further . The removal of the IR filter removes most of the colour information from the images , in essence leaving monochrome images , whereas the "Low Lux" retains a fair amount of colour information , see the Lunar Eclipse images of this site and compare with the "Nightshot" images of The Pleiades .
These functions allow imaging of stars , bright clusters , constellations and to a very limited extent images of M42 , the Great Orion Nebula . In addition reports have been made of capturing meteors with the video camera , showing more meteors than could be seen with the unaided eye . This should prove interesting for imaging meteor showers .
The Lunar Eclipse images , some constellation images and the Pleiades video images on this site are made using the "Camera Direct" technique , using a consumer type digital camcorder with or without a teleconverter . When using the zoom of the camera make sure to use ONLY OPTICAL ZOOM since any amount of digital zoom reduces the amount of detail in the images .
Using the "Camera Direct" method for astroimaging is recommended , especially if a telescope is out of the economical range and the camera is available .
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