Astrophotography using either Film, Digital or CCD imaging devices.
The subject of astrophotography is rather large to cover in a short article but here's a brief outline of the several ways to take pictures of the night sky.
- Camera on tripod with long exposure.
- Camera on equatorial mount or piggybacked on a telescope.
- Pointing the camera at the telescope eyepiece.
- Camera attached to the focuser of a telescope.
The first method is the simplest. Using a single lens reflex camera mounted on a standard photographic tripod, pointing at the sky, and using a long exposure, will reveal the night sky beautifully. The classic photograph that everyone has seen is the star trails produced as the Earth spins on it's axis (if you have a computer, we offer our 21-day FREE trial 'Astro Video' CD which will recreate the star dots from star trails). Use a standard 50mm lens on a 35mm SLR at the widest aperture and with the lens focused on infinity. Exposures as short as 10 seconds using a 400ASA film will freeze the stars' motion. Longer exposures will produce some blur but reveal more, particularly the different stellar colours. Try it and see.
Mounting a camera piggyback on an equatorially mounted telescope means that you can now follow the stars as the move. This allows longer exposures that will have pin point stars and lots of them. Any subject in the foreground though will be blurred such as the trees. Use the telescope's slow motion drives to follow a star in the centre of the eyepiece, or if you have one, turn the electric drive on. (n.b.This method will not work with an alt-azimuth mount). Longer focal length lenses can be used to take in smaller areas of sky, but normally not more than a 150mm focal length is recommended.
Afocal Projection is quite easy. This is where you line the telescope up with the eyepiece and focus as normal. It's easier if the telescope has an electric drive. Then with the lens still on the camera photograph through the eyepiece of the telescope. The photograph above was taken using a Sony digital camera in manner. Lots of photos were taken and the best ones kept, the rest were erased from the disc. This method also works quite well with a video camcorder used to photograph the moon.
Prime Focus. Removing your eyepiece and, in its place, attaching the camera to the telescope's focuser is a slightly more difficult way to do astrophotography, but it produces the most dramatic results as long as you have the patience. Here you are using the large light gathering capability of the telescope. The lens of the camera is removed and the telescope becomes, in effect, a massive telescopic taking lens. If the eyepiece is not used it is called Prime focus photography.
Eyepiece Projection. If the eyepiece is used as well, which increases the magnification (and difficulty) it is Eyepiece Projection. With both types of photography accurate tracking of the sky is essential to make sure that the stars do not trail.
Astrophotography with Video
CCD Video Cameras have one advantage over a stills camera in that the image can be viewed immediately on playback. Video is also useful for capturing occultation's of distant stars by foreground objects such as the Moon and asteroids .
The Widescreen Centre offers the popular STARLIGHT XPRESS CCD CAMERAS for this purpose to image the night sky, and the images can viewed on a suitable PC. Please see the list of products below for fuller details or call Simon on 020 7935 2580 or email him at firstname.lastname@example.org
We are working on new products in this area so keep an eye out on our NEW PRODUCTS page for the first announcements.
Astrophotography with CCD Cameras
Firstly lets clear up a common misconception about the CCD cameras. These cameras are just the capture device. A computer is connected to them and this is the 'film'. These cameras are not the 'digital cameras' advertised in photographic magazines but highly specialised pieces of equipment.
The CCD camera is basically a CCD chip that is cooled in a housing. Onto this chip falls the light. After the required length of time a signal is passed to your computer which produces the image on your screen. The image can then be manipulated to get the most out of the information recorded.
The chip is made from so many pixels. Small electronic elements sensitive to light. The more there are the sharper the image looks and the larger the resulting file size in the computer. The larger the chip generally is, the more it costs to buy. The small size of the chips makes aligning them on target harder than for film cameras but you do at least know straight away if the image is any good.
USE THE CAPTURED IMAGES...
...in conjunction with our Astro Imaging Enhancement Software (available on a FREE 28-day try-out basis) to produce your best-ever images.
This CCD Electronic Imaging Eyepiece offers you the simplicity of plug-and-play and ease of use, plus an affordable way to share the wonders of nature or the night sky with others.