And here's an explanation from an interview with Dr. Neil deGrasse Tyson (American astrophysicist and Director of the Hayden Planetarium at the American Museum of Natural History in New York City) on the Scholastic News web site about the debunking described in the video:
People come in here [Hayden Planetarium] assuming that they'll get their horoscope. They don't know that astrology has been [disproven] for centuries, but it's a billion-dollar industry, so it's not going away soon.
I did this experiment in a college class. I found some widely read horoscope column, and I said, "Pick one at random, and put it on the wall. Is this your horoscope, or not? Type yes, no, or maybe." Eighty percent of the people thought it was their horoscope!
Some sleepless, creative person 5,000 years ago invented the constellations. If we were to make constellations today, there'd be no serpents. There'd be a cell phone and an SUV and a microwave oven and a baseball field. There would be things that are in our modern culture, expressed in the legends of the sky.