The Knickerbocker Chamber Orchestra’s debut concert last Saturday night drew several hundred people to the World Financial Center Winter Garden. Left, guest Elizabeth Pitcairn plays a suite from the movie “The Red Violin” on her 1720 Stradivarius that shares the movie’s name, while orchestra founder Gary Fagin conducts. For the orchestra’s final number, Fagin invited the audience to waltz to “On the Beautiful Blue Danube.” Several dozen couples took him up on the offer, including Pitcairn and her friend Clayton Cowell.