Image Size and Resolution
Here we have the same
image at 3 different sizes. The image in the middle
is 10 times bigger than the image on the left, and the image on the right
is 10 times bigger than the image in the middle. So now you can see that
the size of the image produced by a detector is important to an astronomer.
In fact, using the tiny image on the left, we would have no idea what we were
looking at, but only that "something" is there. The image in the middle
would allow us to say that the "something" is a human being. The image on
the right would allow us to identify the "something" as a painting of Paul
But image size is only a part of the whole 'image' issue....you also need
to understand about image resolution.
Here we have the same image at the same size, but at 2 resolutions.
The image on the right has 9 times the spatial resolution as the one on the
left does. What a difference! Now you can see why having a value of the
spatial resolution be as big as possible is very important to an
astronomer... the bigger (or better) the resolution, the more you can see the
details, and the more you can learn about something.