1534 Näsi, provisional designation 1939 BK, is a rather eccentric, carbonaceous asteroid from the outer region of the asteroid belt, about 22 kilometers in diameter. It was discovered by Finnish astronomer Yrjö Väisälä at Turku Observatory, Southwest Finland, on 20 January 1939. The minor planet's name is derived from the Finnish lake Näsijärvi, sometimes called "Näsi". The large lake measures 256 square kilometres (99 sq mi) in size and is located only 95 metres above sea level.