BBC’s “Doctor Who,” one of the longest-running shows on TV, returns tonight at 9 p.m. on BBC America. The finale of this season’s first half, “The Angels Take Manhattan,” was filmed earlier this year in several locations around Manhattan, including Central Park and outside the United Nations building. According to a Nielsen report, “Doctor Who” has upped its U.S. appeal over the past year. Last year’s season premiere drew 1.3 million viewers. The year 2013 marks the 50th anniversary of the sci-fi series.