If you use the Canon D60, the battery is rechargable and lasts a long time. It's Lithium Ion. You can buy extra batteries. The charger charges two at a time, if you like.

The big issue with digital cameras is noise. The SBIG CCDs chill the CCD chip to -50 C. You'll probably be operating your camera around 15 to 20 C min the summer. That means lots and lots of hot pixels in the summer.

In a time exposure, heat builds up inside the camera. With a D30, the practical limit is about 2 minutes at 100 ISO. The D60 has less noise and better signal processing, so you can get a minute or two longer.

You'll see people getting as much as 5 minutes minutes at 800 ISO with the D60. You need to know how to process those images, since they'll be full of hot pixels. You need a dark screen image to remove the noise. And, what people forget to tell you is that the noisy pixels cost you information.What if there really is a star at a place with noisy pixel and its equal in magnitude to the dark frame image? The image processing you do will subtract it.

I find it best to stick at 100 ISO with these cameras and up to 2 minutes with the D30. Preferably 1 minute.

Now, if you want to do solar, lunar, or planetary shots, this is sufficient. Most deep space objects are too faint.

I haven't tried integrating images with these cameras. Perhaps you could get some nice images of globular clusters by stacking your images.

Mitch