The position or aspect of a heavenly body, as the moon or a planet, when half way between conjunction, or opposition, and quadrature, or distant from another body 45 degrees
a measuring instrument for measuring angles to a celestial body; similar to a sextant but with 45 degree calibration
> The backstaff was an early navigational instrument used to gauge latitude at sea It was replaced by a more accurate device called the octant The octant was replaced by an even more accurate instrument, the sextant, which is still being used today Note: Latitude is the distance north or south of the equator, which is measured on a map or globe in degrees along a meridian