Guys,
Both the 300D and D70 make excellent astrocameras, the D70 requires the 'mode 3 trick' to generate true raw images. If you are intending to do the H-Alpha enhancing mod, the D70 may actually be a better option.
I own the 300D (with the IR filter replaced with a Baader UV/IR) and am very happy with it. If you have a 300D can I suggest the 50mm f1.8 lens - if you get hold of a cheap mark I version with the distance scale even better. Here are some recent results I have been getting with this lens:
http://www.pbase.com/terrylovejoy/50mm_f18_ef
Can you do daylight photography with a modified camera? Yes you can, but its harder to get acceptable results. Here are some examples:
http://www.pbase.com/terrylovejoy/po...aylight_images
The bird shot was made by taking the standard Canon filter and mounting it on a 58mm filter ring and screwing it onto the front of the lens.
I am now using dcraw to modify colour balance automatically from raw files and it works well.
Terry