Hi Jay, thanks for that, now you have a new camera you have guaranteed we will have clouds here in Melbourne for at least a week!
But seriously, I assume that since you have an ASI290MC you will be looking at planetary imaging (and now is the best time to do it). If you haven't already watched these videos, I would highly recommend them.
http://planetaryimagingtutorials.com/
I use FireCapture with my ASI224MC and can highly recommend it (there is a tutorial video included in the link above), I assume a BT200 F/5 is a 200mm Newtonian F/5, so with the 290MC you will want to image the planets at about f/15 (so the 2.5x Barlow should work well).
Focusing is hard, and takes a bit of getting used to - I myself use a piece of pipe foam insulation over the focus knob and one of my wife's long hair clips attached to it to give me (almost) vibration free manual focusing.
Hope this helps,
Andrew