Ensign Lydia Monks, operations officers temporally assigned to the Coast Guard Cutter Forward, a 270-foot medium endurance cutter home-ported in Portsmouth, Va., uses the sextant to plot her cutter's track line Wednesday, Sept. 18, 2013. The sextant is used is to determine the angle between a celestial object and the horizon which is known as the object's altitude, and the data gathered can be used to calculate a position line on a nautical chart. (U.S. Coast Guard photo by Petty Officer 2nd Class Michael De Nyse)