SEXTANT SIGHTS U.S. Navy Ensign Rachel Herrera uses a sextant to determine the distance from the amphibious dock landing ship USS Pearl Harbor to the Military Sealift Command dry cargo and ammunition ship USNS Mathew Perry before a replenishment at sea, Aug. 8, 2013. SHARE: Download: Full Size (0.07 MB) Credit: VIRIN: 856160-Q-NWH80-363.jpg Photo Gallery