Re: can a tunable video camera be built?

Let me answer your question by asking one of my own:

With today's technology and knowledge, if money wasn't a problem, could a car be built which would drive on roads, and over the oceans, and fly through the air, and climb in trees, and walk up stairs?

The answer to my question is: yes, if money wasn't a problem, one could probably hire a team of experts in a range of different transportation fields to design a single device which would perform all of these tasks. It would very probably end up not doing any one job -- say, driving down a narrow street -- as well as a device specifically suited for that one job.

If what you really want is to travel to many types of location, it's a better idea to use a car when you're on level ground, and to use a boat when you want to go over water, and to use a plane when you need to fly. There's no good reason that I can see for trying to make a single vehicle which handles all types of terrain.

I think the best answer to YOUR question is similar. Yes, I suppose that if you spent enough money, you could have someone build you a single box which would detect light of a very wide range of wavelengths. However, as far as I know, it would have to be made of a mix of detectors: there would have to be one set of devices to take images in the optical and near-IR, another set of devices to make images in the far-IR, a rather large structure with one or more dishes to detect longwave radio, perhaps a scintillation counter to detect gamma rays. Each set of detectors would have its own separate mechanisms to focus, to point, and so forth.

I suspect it's not the answer you were hoping to see, but I think you'd be much better off carrying a few, simple devices instead: an ordinary camera, an ordinary radio (or maybe a couple of them), a Geiger counter. You wouldn't really be creating images at all wavelengths, but you could purchase them all for a few hundred dollars and fit them all into a backpack.