basic astrophotography questions

Hi all,

Maybe I should post this on one of the other forums, but these are newbie questions.

What's the basic difference between using a CCD camera versus a digital camera such as the Canon EOS 20Da? Overall, if I spend that much for a camera, I'd like to use it for other things as well. Does the CCD take better shots because of the cooling? Or, are there other differences?

Also, why are most shots taken with refractors? Is the high f/ number better? I would have thought reflectors are better because of their higher light gathering capabilities. Are refractors easier to focus?

TIA.

>>What's the basic difference between using a CCD camera versus a digital camera such as the Canon EOS 20Da?

The CCD has cooling, and probably a better chip in the first place. Therefore, it has a higher top end. However, it is usually black and white, whereas Canon is single shot color. On the other hand, you have a lot more control over the color in a CCD, probably. In short--A Canon will get a very good picture, but a CCD will get even better.

Of course, the DSLR has a much easier learning curve, so you will be getting that picture sooner than with a dedicated CCD.

>>Overall, if I spend that much for a camera, I'd like to use it for other things as well. Does the CCD take better shots because of the cooling? Or, are there other differences?

Yes, the cooling is a big deal, but there are other differences, also. Resolution is probably better in a CCD. The other differences are too technical, here.

>>Also, why are most shots taken with refractors? Is the high f/ number better? I would have thought reflectors are better because of their higher light gathering capabilities. Are refractors easier to focus?

Ther is no inherent reason you cannot take astro images with a reflector, and depending on how well it is made, collimated, etc, it can get pictures as good or better. But you can probably get smaller stars with a refractor, and small stars are what you are after. You can probably mount a small refractor much more easily than a large reflector, also.

Alex

Doug: I am a beginner at digital photography. I went the CCD route with a used SBIG ST237A and I use only 35mm lenses to simplify alignment and guiding requirements. I picked the ST237A because SBIG makes a great camera and has mature software support; and I could pick up a camera for around $600. I already had a good mount (Losmandy G-8) and I wanted specifically to try the CCD route. However, if you want to go really widefield, then a Digital Rebel may be the way to go as my max FOV is something on the order of 4x5 degrees with the 50mm lens. Widefield with a CCD chip the size of a Canon D20 or XT is going to cost lots of cash.

Ed Wiley