Galileo (who'm we celebrate next year with the international year of astronomy) had three things running for him: he could use a telescope and unveiled the universe to the world thanks to his practical abilites, his theoretical knowledge and his eloquence.
Copernicus had it right, but never published his book during his lifetime.

What Galileo once wrote, here:
If the progresses made by the refractor were to go together with those of the other great inventions, we can hope that, with time, we'll be able to see things that , today, to us, are unimaginable.

(It might not be found written this way in the link, because mine is a translation from french).