Hubble is too close and so unusual because too little money has been spent on space. In a civilised community we should by now have the equivalent of Hubble (or better and for other purposes as well) round every major body in the Solar system, including functional exploratory craft in the Kuiper belt.

The cost would be trivial, but instead we spend our money on politics, politicians, war and waste.

That is much easier.

Putting the Hubble out beyond Pluto would not move it significantly closer to anything else. That's only about 7 light-hours out. There is no significant obstruction to viewing within the solar system, provided you avoid looking directly at the big objects (they will move out of the way soon enough).

It's kind of helpful to have the Hubble in our own backyard, too. It has had a couple of upgrades and refits by the Space Shuttle so far, and we can't do that even as far out as the moon.

Also, the thing is directed by radio from Earth and the images returned the same way. It would need considerably more autonomy to deal with even a few minute's latency in the message turn-around time, and a major increase in transmitter power.

Finally, Hubble is powered by solar panels, whose output falls off with distance from the Sun as an inverse square. Voyager and others carried RTGs (radioisotope thermoelectric generators) for power.

Paul, you are looking pale and anonymous! What happened to your portrait?

>Putting the Hubble out beyond Pluto would not move it significantly closer to anything else. <

True as far as it goes, though there are other observer functions than peering beyond our heliopause. However, what is more important than getting closer to our neighbours, is getting further from our own noise, which is horrendous, and getting further from other observers so as to maximise our base for long-distance observations.

>It's kind of helpful to have the Hubble in our own backyard, too. It has had a couple of upgrades and refits by the Space Shuttle so far, and we can't do that even as far out as the moon.<

Several acerbic responses to that one are available! If ever there were a reason for designing disposable craft, putting them out beyond a ten-year maintenance voyage would be one of them! Cutting our coat according to shuttle cloth is a political CYA for the parties who sold NASA down that river. The reason the shuttle can't do a decent job of more remote work is that it is a crappy design, ad hockery, a ponnery. Another disgrace is that the shuttle is on the junkheap and they haven't even settled the technology of the successor! The stench of politics is nauseating.

>Also, the thing is directed by radio from Earth and the images returned the same way. It would need considerably more autonomy to deal with even a few minute's latency in the message turn-around time, and a major increase in transmitter power.<

Not really. There is a need for classes of craft. Those within Earth/Moon range would be the rapid response, hands-on control units.  Those hiding in the shadow of Mars would be same-day service. Those beyond Neptune would work on schedules planned months ahead, if not years or decades.