|
The ASI290MC has smaller pixels, so it will capture slightly less light than the 224, however on a 10" dob it shouldn't make any measurable difference. I would not consider buying the 120MC, sure it's cheaper, but it's cheaper for a reason.
The f-num = 5x pixel size still applies, although for the 290 the optimal f-num is around f/15, not f/20. What f-num do you get with your dob and 2x Barlow?
The Canon 30D does not have Liveview, so will not be any good for planetary in the way I mentioned above. You might be able to get a good used Canon DSLR second hand off eBay, Gumtree or even Crime Converters - make sure you do NOT get the 650D, it's terrible with LiveView.
Andrew
|