I have a mint condition Pentax K-r DSLR, 18-55 lens and the O-GPS1 unit that allows you to do long star exposures using just a standard tripod.
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http://www.digitalcamerawarehouse.com.au/prod8615.htm)
This works a treat, you can shoot wide long exposures of the sky without having to have a polarie or tracking mount.
The sensor inside the camera rotates to track the star movement, so no need for a tracking mount.
It is also an excellent DSLR and the O-GPS unit works as a standard GPS for photo taking. It will also work with other Pentax DSLRs.
The K-r allows any lens to have anti-shake characteristics as the anti-shake system is built into the camera itself.
$650 ono for the lot.
NOW $550