If you want to get into astrophotography you have to consider buying a camera. But before you go rushing toward your favourite electronics store, you have to decide what type of camera you want. In general there are four main categories: point-and-shoot, single lens reflex (SLR), web cam and CCD.
Such cameras are also called snapshot cameras. These are the most inexpensive cameras for general photography. They have a fixed lens and very basic functions. When in manual mode, the point-and-shoot cameras have very limited maximum exposure time. Also, most aren’t that great in low light conditions. You have to invest a bit more for a higher quality point-and-shoot camera.
SLRs or the nowadays more common digital SLRs (DSLRs) are more expensive than the simple point-and-shoot cameras. A major plus is that they have removable lenses and you can have an entire arsenal of focal lengths to play with. They image quality is also superior to their cheaper cousins.
Web cams are very inexpensive and these days almost anyone has one. Not all web cams can be used for astronomical purposes though. They have very small detectors, which results in very tiny fields of few. Because they record video, you have to use software to “stack” the individual frames and create a final image. And unless you buy a dedicated astronomical web cam, you will need to modify it so that you can attach it to astronomical equipment such as telescopes or lenses.
CCD Cameras for Astrophotography
These are special cameras specifically made for astronomical purposes and therefore on the expensive side. CCDs produce the highest image quality. On the downside you need to photograph the same object (at least) three times using different filters (red, green and blue) to create a color image. CCDs also have tiny detectors and very limited field of view.
How to choose the best camera?
Do you already have a camera? Star with what you already have and see what you can get out of it before investing more money. For those of you that don’t have anywhere to star from a different question awaits. What type of astrophotos do you want to take?
These are the wide field of view targets such as twilight, Milky Way, zodiacal light, aurora, constellations, etc. Pretty much everything that doesn’t require guiding and could be photographed within a few tens of seconds. Here your best friends are the point-and-shoot and DSLR cameras. They are the only ones that can capture such sceneries.
This category encompasses the objects in our solar system – planets, Sun, Moon, etc. To capture details of these objects you need very high resolution. While this could be achieved with DSLRs and CCDs, the best way to go here is using web cams. Recording video allows you to capture hundreds of individual images with very short exposures. As a result you are able to gain the most amount of detail, because there’s no time for the constantly boiling atmosphere to blur your images. In fact, the most stunning planetary photographs are made with web cams.
Deep Sky Objects
Deep sky astrophotography requires very long exposures and detectors with very low noise. The two alternatives here are DSLRs and CCDs. In general, CCDs have the lower noise levels of the two, and can produce images with higher quality. However, they are more expensive than DSLRs, have smaller filed of view and require taking exposures with multiple filters to capture a color image. The image quality of the DLSRs very high (and increases every year), which allows them to capture very spectacular images as well.
If you want to invest some money into camera for astrophotography and you are just starting out, a good option would be a DSLR or even a good quality point-and-shoot camera. Both can be used not just for astrophotography, but also for taking photos during the day (family, nature, etc.).