Tony, Canon announced the 20DA a week after I bought my 20D, .
from what I have read it has a built in infra red filter (or maybe the ability to cutoff same) . The mirror can be locked up on the 20D
but the image can also be displayed on the LCD rear screen on the 20DA The nice thing about the Canons is that they're very low noise, my 20D goes to 3200 ISO and the noise is still quite low at that speed. Most consumer cams crack up at anything over 200 ISO. Go on buy it, you'll need one for that 16" Meade!! I've noticed that on some other sites there are mentions of firmware hacks and I'm hoping the LCD rear display option shows up either as a Canon update or a hack sometime. Once I make a decent adapter for my Zippo Bushnell (ex cupboard relic) I'll post some images at 3200 ISO. $1500 won't even get you a lookin; body only for the 20D only in Oz is around $2400, the DA will probably be dearer.