Convert from gigaparsec to shaftment [ancient]

Unit Definition (gigaparsec)
The Gigaparsec is a non-metric unit of distance equal to one billion parsecs, 3.2616 billion light years, or 30.856 78 zettameters (30.856 78 x 1021 kilometers). The unit is used in astronomy.

Unit Definition (shaftment [ancient])
A shaftment, when used as a unit of length, is usually six inches or two palms, i.e. 15.24 cm (for the international inch). It is thought to be the distance from the tip of the outstretched thumb to the other side of the palm.In English this unit has mostly fallen out of use, as do others based on the human arm: digit (1/8 shaftment), finger (7/48 shaftment), palm (½ shaftment) hand (2/3 shaftment), span (1½ shaftments), cubit (3 shaftments) and ell (7½ shaftments).