It is the most distant outer planet from Earth. Neptune is a cold and distant world. It is about the size of Uranus, however it is about 50% times further than its light blue cousin.
Despite its large size (almost four times larger than Earth), Neptune was only discovered in 1846 and has only traveled one orbit since its discovery!
Observing its pretty blue color is pleasant, especially when you know that you are looking at an object more than 4.3 billion km away.
Select another planet to observe with a telescope
Image credit of Neptune: Justin Cowart / CC BY (https://creativecommons.org/licenses/by/2.0)