Jupiter

When the Hubble space telescope was launched it has blurry vision, so Astronauts got their space-spanners out and fitted corrective optics (contact lenses) to the telescope. With its contact lenses fitted Hubble has given us great views of the stars, and some pretty good views of Jupiter. Go back to 1979 and the Voyager spacecraft both went past Jupiter and, whilst a little grainy, their postcards home were enlightening - you could make stuff out.

Before all of this Earth based telescopes probably gave us really blurry pictures of our neighbouring planets. Jupiter probably looked like this picture - taken in my pocket.

Just be glad I'm not talking about Uranus.