NEW Brass Sextant Nautical Brass Sextant Working Marine with Box ~ Nautical Brass Working Marine Sextant ~ Navigation Ship Decor Sextant with box - Replica. A sextant is an instrument used to measure the angle between any two visible objects. Its primary use is to determine the angle between a celestial object and the horizon which is known as the altitude. Making this measurement is known as sighting the object, shooting the object, or taking a sight. The angle, and the time when it was measured, can be used to calculate a position line on a nautical or aeronautical chart. A common use of the sextant is to sight the sun at noon to find ones latitude. It’s all parts are moving, can be used for basic observation or suitable for collectors and can be a gift for someone