How Can a Single Radio Telescope Distinguish Between Point and Extended Sources?

[mordeth]

If you were using a single radio telescope (not an interferometer) how could you tell whether a radio source was a point source or extended source?

I have searched the internet far and wide for many hours trying to answer this - I know what the difference between a point source and extended source is, but I'm not sure whether the question is asking for a simple or technical explanation. Is it something to do with the radio telescope data or how the radiation from the source is spread out on the dish when its received?

 

[jimgraber]

I assume you mean the usual in-effect single-pixel radio telescope at a single point in time. Then it is pretty much impossible to tell the difference, I think. The usual method then is to look at different points at different times. i.e. scan out the image over time. You can then detect its size, assuming its pretty much a constant source and really bigger than one pixel.

Jim Graber