I understand that the bigger your telescope’s dish/mirror, the more information you receive and the better your image/data. But why does an array of relatively small dishes spread out over a mile (for example) get treated as having similar data collection powers as a single dish a mile across?
It’s this lazy reporting? Me misunderstanding? Some complex concept that I don’t understand?
Logically (to me) three twenty meter dishes should only collect three times the data of a single twenty meter dish. What an I missing?
In: 5
That’s a bit complex … not sure if I can actually ELI5 it.
Maybe a visualisation helps, though it might not be entirely correct.
For a telescope the resolution is calculated by the wavelength and the diameter of the mirror. The larger the mirror, the better the resolution.
Now imagine a 100 meter diameter mirror. It has some resolution. If you make a hole in it, the diameter stays the same. So the resolution is the same. If you keep making the hole bigger, the diameter will still stay the same, although most of the mirror is gone.
Where this now breaks down is that you have a ring instead of two single points. But now imagine you split the ring in multiple segments, now you have a lot of single mirrors but the resolution still stays the same. Not a perfect analogy, but the basics are still the same. In terms of resolution two distant dishes (in Radio) working together have the same resolution as one big dish.
The difference is the mich lower collectin area which collect the light and reflect it to the receiver.
But the advantage is that it is much easier to build.
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