Who--astrologically speaking--is Harry Potter?
The planet Mercury, always present in acts of magic, is the messenger between the ordinary and non-ordinary worlds. In this version of Harry's chart, both the sun and Mercury come under the philosophical, expansive, and positive influence of Jupiter. This gives us a character somewhat like Disney's "Lion King"--the lion is the symbol of the astrological sign of Leo--who must meet many challenges before assuming his rightful place. In this chart, too, Harry's Jupiter has an exact trine (positive aspect) to Neptune in Sagittarius, suggesting his place in a royal lineage of magicians as one with vision and the magical power to achieve the improbable. (It doesn't hurt his Quidditch game, either!)
With a moon in Libra, we would expect Harry to be kind, considerate, and of passive temperament in his early years. This aspect also suggests steadfast and helpful companions--for example, the faithful Hagrid, Ron, and Hermione. As a name, Hermione is another word for the god Hermes or Mercury, and Hermione does function like Harry's sun conjunction to Mercury--knowing all the incantations and rituals required for the successful execution of magic. (In Book 3, "The Prisoner of Azkaban," we find that Hermione is almost certainly a Virgo.)