The connections are quite simple-
- 12 Sides of the Star of David = 12 Signs of the Zodiac
- 7 Planets of Astrology = 7 Parts of the Star of David
Classical astrology and the Hexagram, unsurprisingly, fit very well together. The astrological associations are shown above, with the twelve signs of the zodiac lying in order within the six points of the Hexagram and the six vertices between them. The Seven Planets of classical astrology correspond to the six points of the Hexagram and its center.
– The Hexagram, Byzant.com