Much have I travelled in the realms of gold
And many goodly states and kingdoms seen;
Round many western islands have I been
Which bards in fealty to Apollo hold.
Oft of one wide expanse had I been told
That deep-browed Homer ruled as his demesne;
Yet did I never breathe its pure serene
Till I heard Chapman speak out loud and bold:
Then felt I like some watcher of the skies
When a new planet swims into his ken;
Or like stout Cortez when with eagle eyes
He stared at the Pacific—and all his men
This compares Keats' feelings of awe to looking through a telescope at the universe in all its beauty. This is a particularly stirring image, as knowledge of the solar-system was expanded by pioneering astronomers such as William Herschel, who identified the planet Uranus in 1781. 
 The poem throughout subtly raises the issue of the discovery of planets and continents, as well as the literature of the past. There is an underlying sub-text that is critical of the vanity of man who thinks he grasps the totality of knowledge and understanding of the world.