By Robin Elisabeth Kilmer To regulars at Riverside Park South, the gathering of people and telescopes under a cloudy sky seemed inexplicable. Confused park goers quickly learned that something special was happening. Behind the curtain of clouds Venus was following its orbit as it has for eons, only this time its path placed it directly between Earth and the sun. For two hours, from 6 until nightfall, Venus would appear as a beauty mark on the visage of the sun. This visible transit happens in pairs; when one occurs, another will follow eight years later. Before Tuesdays's event, the most recent transit was in 2004, and Earthlings will have to wait another century for the next one. The transits are easily predicted, but the weather is not. Astronomers fretted as clouds hovered over Manhattan for most of the day. A little past 6, the clouds parted over Riverside Park's Pier One, granting spectators a view of the show. The event, hosted by the Amateur Astronomers Association of New York, had drawn roughly 1,500 people. "I lost count a long time ago," said NASA Solar System Ambassador Jason Kendall. (http://nypress.com/wp-content/uploads/2012/06/antique_telescope.jpg) Solar glasses were distributed to the crowd and astronomers manned their telescopes, which came in all shapes size-the most unique being an antique French made telescope that one man had inherited from his great-grandfather. "I bet he saw the 1874 and 1882 transits on this," said the man, who let Margarita Abadie borrow his telescope. Abadie, an astrologer, explained the fortuitousness of the transit. "It's about bringing forth the positive and suppressing the negative." Among the spectators was four-year-old Jacob Plager, who came with his father and little brother. Plager has been learning about the solar system in school. "Pluto is just a little ice ball," said the knowledgeable four-year-old. His thoughts on the transit of Venus? "It was very cool."