New York City Opera, which filed for bankruptcy protection last month after years of management missteps, won court approval to auction some assets, including costumes, wigs, props and about 60 musical instruments, Bloomberg News reported yesterday. The public sale was approved on Tuesday by Bankruptcy Judge Sean Lane. The auctioneer, Tiger Remarketing Servicing LLC, will get 10 percent of the proceeds from the sale, which also includes the opera’s gift shop inventory of CDs and books and a harp at Lincoln Center in New York. Stock scenery, tools, stage curtains and prop fabric at the opera’s facility in New Windsor, New York, will be auctioned, as will computers and office furniture from the opera’s office on Broad Street in Manhattan, according to a Nov. 6 request to approve the sale.