Why 13 Signs?
The constellation, Ophiuchus, has been known since ancient times, and is better known as Serpentarius, the Serpent Holder. It is included in the list of 48 constellations described by Ptolemy. Ophiuchus is depicted as a man handling a serpent; his body dividing the large snake into two parts, giving way to the symbol used today as an Asclepius – the medical staff.
Astrologers have not included Ophiuchus in the wheel of Astrological signs because the Sun spends only about nineteen days in this 13th sign of the Mazzaroth.
The Sun, for 19 days of the year, travels through the star constellation ‘Ophiuchus’ before entering Sagittarius from Scorpius The sign of Ophiuchus is patterned after the original ‘Serpent Holder’, Enki a Sumerian god.