There is much misinformation on the web about occultic misappropriation on the Magen (Star of) David, and there is a wonderful article on The Refiner's Fire explaining this issue.
Rephan is another name for Molech or Baal, this time coming more from the Amorite, as opposed to Canaanite or Babylonian versions of this popular false god. Many, as you know, burned their children alive to this deity, earning the outrage of prophets like Amos. Rephan also refers to a celestial body that was called a star but which we now refer to as a planet. On the other hand the word "planet" is from Greek "planete" which is in turn a shortened form of "planes aster"--moving star, so in the ancient minds stars and planets were kind of the same.
Notice also how the rebuke is for worshipping the stars as gods which is also associated with the time Israel was in the wilderness. This was absolutely the worst kind of idolatry imagineable, way worse than the sensuous sins of the Greeks and Romans, and yet Israel participated in it with the nations around her. Any wonder both Amos and Mar Stephen were so angry!