Below is a comparison of the four gospels and how each represents a different aspect of Christ's character and purpose. Then I compare that to the living creatures, the constellations, their locations, the tribes, and the gemstones.
Confusing, unless you go back to when Libra and Scorpius were considered one constellation. Scales are symbolic of judgement and the eagle is the enemy or judge of the serpent.It is possible that the scales are really eagle's wings (or symbolic of such) about to land on the serpent or scorpion. It is also interesting that the sun is in Ophiuchusthroughout almost all of the time given to the sign of Scorpio, such that it may be the serpent wrestler, and not the serpent, that is represented.
Dan (referred to as both a serpent and a judge).His emblem was the Eagle. Although Dan has been represented by the sign of Libra due to the judge factor, I see Ophiuchus as the most likely candidate for the Eagle due to his fight with the serpent and his location as one of the four main points of the zodiac.