Why is this highly distributed array a bad idea?

[jshrager]

I once ran into a nobel-winning astronomer at a conference and suggested to him putting small internet-controlled telescopes for free (and fully supported) on a the roof of any household that wanted one. The telescopes would be controlled by "The Project" from a central server, and the "owner" (that is, the person whose roof it is on -- the real owner being The Project) would be able to use it at any time they desired through a web interface, with the proviso that whenever the "owner" is not using it, it can be used by The Project (remotely controlled). Presumably a lot of people would want this (hey, free toy!), but on any given night (esp. at 3am!) most of the scopes would remain un-used (by the "owner"), and so would create a gigantic distributed telescopic array all over the earth! My BoTE calculation was that this would cost about 1/1000 of what "big" scopes cost today per collection area. Of course this needs to be moderated by parallax and other complexities, but would have many additional advantages of usually good viewing conditions (someplace) and extremely broad base. The astronomer said it wouldn't work, and gave me a very quick explanation that I didn't understand (mostly because, being a chance hallway conversation, he didn't have time to explain himself there and then). Can someone tell me why this is a bad idea?

 

[Wallace]

The power of telescopes isn't just in their size. In order to collect useful information, the receivers (the part that actually picks up the signal that has been focused by the dish part) have to have low noise, very accurate timing etc etc. These things are expensive and require a lot of careful maintenance and calibration. You can't just install them and leave them there for ten years. That is the first problem.

One of the other issues is interference. One of the hardest things about observations of correctly accounting for that which requires some reasonably complex techniques (that I don't know too much about as I'm not a radio observer). Suffice to say though, that it gets much harder if every little receiver is in a different place with a different set of interference problems. Telescopes tend to be very carefully sited in remote locations, trying to do radio frequency observations in a modern city would be impossible because of all the interference.