is Severus Snape's birthday.
Wow, who would've thought? A Capricorn!
And according to
http://www.spenecial.com/birdsofafeather/astrology.htm, here is what his horoscope says:
CAPRICORN
(December 22 - January 19)
The Quinotaur (half goat, half mermaid/merman). Cardinal, earth, yin - planetary ruler: Saturn. Keywords: "I USE"
Capricorn is the tenth sign of the zodiac and governs the bones, joints, and knees. Positive traits include pragmatism, maturity, patience, determination, awareness, a strong work ethic, realism, discipline, money management, the willingness to overcome hard luck, leadership, initiative, opportunism, prudence, and cunning. Negative traits include pessimism, melancholy, emotional coldness, manipulation, obsession with work and ambitions to the detriment of personal development, remoteness, and materialistic snobbery.
More specifically, here is what a Slytherin Capricorn is like:
Slytherin
The traits emphasized here will be ambition, determination, discipline, and pragmatism. You can't make that castle in the sky if you don't build a solid foundation under it, and Capricorns excel at building foundations. (Actually, they excel at planning the foundations and directing others to do the grunt labour. It's not that they're afraid to get their hands dirty, but large work usually requires delegation and a staff, and Capricorns are managers more often than not.) While not flamboyant or showy about it, Capricorns still tend to be obsessive overachievers, a common trait in House Slytherin. Too, wizards born under the sign of Capricorn are good at being discreet, secretive, and diplomatic; whereas the Libra's diplomacy is based on charm and a desire for harmony, the Capricorn's diplomacy is based on the knowledge that being on good terms with people is extremely useful in getting one's way or finding out sensitive information. These also are traits commonly associated with House Slytherin. They might not be sexy traits, but they're very handy.
I must say that's rather accurate. ;)