What was the first planet to be discovered by telescope?
Only three of the eight planets in our solar system have been officially discovered as the human eye can see all other planets without assistance. Uranus was the first planet discovered in 1781 by astronomer William Herschel, however he originally thought the planet to be a comet. Herschel is regarded as one of the most famous astronomers of the 18th century as he observed and catalogued over 800 double stars and 2,500 nebulae. He was also the first astronomer to accurately detail the structure of the Milky Way Galaxy.