Convert from stadium to astronomical unit

Unit Definition (stadium)
The stadium is a historic unit of distance originating in ancient Greece. Greek athletic fields were all of roughly the same size, and the stadion, equal to 600 podes (feet), was the traditional length of the field. Archaeological measurements show that the stadion was a little more than 200 yards or a little less than 200 meters. The stadion at Olympia, where the original Olympic Games were held, measures 630.8 feet or 192.3 meters; at Athens the stadion was 606.9 feet or 185.0 meters. Stadium is the Latin spelling; in the Roman world the stadium was equal to 625 Roman feet (pes) or 1/8 Roman mile. This is equivalent to 606.95 feet, 202.32 yards, or 185.00 meters. The plural is stadia.

Unit Definition (astronomical unit)
An Astronomical Unit is approximately the mean distance between the Earth and the Sun. It is a derived constant and used to indicate distances within the solar system. Its formal definition is the radius of an unperturbed circular orbit a massless body would revolve about the sun in 2*(pi)/k days (i.e., 365.2568983.... days), where k is defined as the Gaussian constant exactly equal to 0.01720209895. Since an AU is based on radius of a circular orbit, one AU is actually slightly less than the average distance between the Earth and the Sun (approximately 150 million km or 93 million miles).