FILE – In this Jan. 30, 2006 file photo, Nantucket Lightship sits anchored at Rowes Wharf in Boston. Its powerful beacon will be lit for about two minutes for the first time in 40 years Friday, Aug. 7, 2015, then powered down again. The lightship, which operates as a museum, received special permission for the one-time event in Boston Harbor because its bright beam — designed to be seen for 23 miles — affects nearby Logan International Airport. (AP Photo/Chitose Suzuki, File)