What kind of things I could "see" with an amateur radio telescope? There are apparently not many reasonably priced radio telescopes available for the amateur users. I only could find a SPIDER 230C 2.3 meter diameter compact radio telescope, which costs ~10 k€. Reading the page, I don't get a good overview what kind of things I could &quot;see&quot; with a radio telescope that has a 2.3 meter antenna.
Is the instrument already a (semi-)professional one?
Rather than looking for ready-made systems, take a look at projects. Right now, plenty of amateurs are using software defined radio coupled to various antennas for astronomy. Start here:
http://www.rtl-sdr.com/rtl-sdr-for-budget-radio-astronomy/
And while it has nothing to do with imaging, there's plenty of radio astronomy that amateurs can do using simple (albeit sometimes large) antennas:

http://radiojove.gsfc.nasa.gov/
http://radio-astronomy.org/pdf/qex/radio-jove-proof.pdf
http://www.radiosky.com/project.html