View Single Post
Old 23-01-2005, 12:15 PM
[1ponders]'s Avatar
[1ponders] (Paul)
Retired, damn no pension

[1ponders] is offline
Join Date: Nov 2004
Location: Obi Obi, Qld
Posts: 18,778
Hi Rodstar.

You can use just about any digital camera or digicam to take Afocal shots. Simply hold it up to the eyepiece and snap away. You may or may not get vignetting. If you use your zoom on the camera to zoom into the eyeiece then you wont get as much vignetting.

What is it. Imaging looking through a piece of pipe. You can only see a small area of the scene your looking at, all the rest you see is the inside of the piple. The inside of the pipe that you see is analogous to vignetting of a photo. Now with the pipe, the shorter the pipe or the closer you get to the other end of the pipe, the less pipe there is to interfere with your view. Your zoom lense achieves the same effect as shortening the pipe.

Unfortuantely your are pretty well restricted to photographing the moon and the planets. As Exfso mentioned your exposure time is pretty limited with normal digital cameras. Its also difficult to hold the camera steady enough to take longer exposure photos. If you mount it on a tripod you can get a bit longer but remember if you mount is tracking then the eyepiece is going to move away from the camera lense. You can get around this by using one of the many digital camera mounting brackets that are available on the web. Most of them simply attach either to the eyepiece or telescope to hold the camera in line with the eyepiec for longer

This doesn't get around the long exposure problems though. For that you need an SLR, either digital or film, that is has a "bulb" setting for long exposure and you are able to remove the lenses from. This will allow you, as Exfso has said, to do prime photography where the telescope becomes the lense of the camera. There are other types of astrophotography other than prime photography using an SLR but it is the most popular and the easiest, relativley.

Nikon, Kodak and Canon have all released relatively low cost digital SLRs with the Canon 300D Digital Rebel seeming to be the most popular with astrophotographers. This is not to say that you should get this one. Many Nikon owners are more than happy with their cameras. There hve been numerous reviews done on these to cameras for astrophotography work. I'd suggest checking out some of these reviews before deciding.

Hope this has helped a bit.
Reply With Quote