With a cooled camera shot noise from light pollution for me starts to dominate readout noise at only 5-10 second exposures for color, so in some sense the mount's stability and tracking matter less... since the ideal exposure time is fairly short. (consequence is that I end up with hundreds of gigs of data to juggle, but I'd rather have to throw more computer power at something then deal with mechanical considerations).
Damn, AUD$6.5k, that's WELL outside my range. I'm lucky here in Western Australia; it's relatively easy to get comparatively dark skies - I've not met any amateurs that have a cooled CCD.
I paid $1700 USD-ish. I'm aware many products have a higher price in AU but that's pretty extreme! :)
OTOH, dark skies plus a view of the southern sky is something to be jealous of. :P
Earlier this year I was in eastern AU (and visited the Anglo Australian Telescope-- an amazing instrument). I was impressed by the skies there, I can only imagine what it's like out west without Sydney right over the horizon.
Very recently CMOS sensors have caught up with cooled CCDs for many purposes and have the benefit of being radically cheaper. There are a couple of vendors with products in the same ballpark as DSLRs with similar sized sensors (though obviously without the benefit of being particularly useful as stills cameras). or hum, are in the US at least. :P
The benefit of the cooled sensor is increased with darkier skies too, due to the relative ratio of sensor noise to sky background shotnoise.
