Spat (angular unit)

The spat (symbol sp), from the Latin spatium ("space"), is a unit of solid angle. 1 spat is equal to 4π steradians or approximately 41253 square degrees of solid angle (sequence A125560 in the OEIS). Thus it is the solid angle subtended by a complete sphere at its center.

The whole sphere contains ~148.510 million square arcminutes and ~534.638 billion square arcseconds.

• Turn (angle) — the plane angle counterpart of the spat, equivalent to 2π radians