Convert from spat to bicron

Unit Definition (spat)
The spat is an informal unit of distance formerly used by astronomers. The spat is equal to the terameter (Tm, or 10E12 meters). This is equivalent to about 6.6846 astronomical units. The origin of this usage is not clear; "spat" may be an acronym for "space unit" or "space-time".

Unit Definition (bicron)
The Bicron is an obsolete metric unit of distance, which was defined as 10e-12 meter or 10e-6 micron. This distance is now called a picometer or picometre (pm). The name is a reference to the double prefix "micro-micron".