Hi Fraser, mate I tend to agree with glen, however if your just trying out astro-photography and you are on a very limited budget try a Prostar LP-Guide camera. They operate very similarly to the zwo ones but much cheaper. A link below, to where I bought mine.
http://www.myastroshop.com.au/produc...sp?id=MAS-025B
And a link to a thread on this site wear I have been discussing this camera with another IIS member. And a test image I did. They are very noisy but with calibration the result is acceptable.
http://www.iceinspace.com.au/forum/s...d.php?t=146329