Standard HyperSpace distance unit
A standard HyperSpace distance unit is the unit of distance in HyperSpace. The correspondence between HS distance units and light-years, metres or any other common unit of measurement is unknown, though some sources hint that a HS unit is at least 0.61 light-years.
Fwiffo gives the distance between Sol and Spathiwa as 143 light-years. The same distance can be measured as 233 HyperSpace distance units, so, if the distance given by Fwiffo is accurate (which is problematic, due to Fwiffo's panicked state at the moment), the length of a HyperSpace distance unit is 0.61 light-years. The Melnorme say that the Sentient Milieu spanned 500 light-years, which would equate to 814 HyperSpace distance units in this interpretation.