I'm going to remove the notion that the ecliptic didn't cross Ophiuchus before 1930, since it is clearly contradicted by 
this: Ophiuchus

The story seems to be that before 1930, the area that now only belongs to Ophiuchus belonged to two or more constellations.
In order to formalize it, astronomers had to choose one.
If they choose one of the astrological signs, they would avoid angering astrologers.
If they choose Ophiuchus, one of the most important documents in astronomy, Kepler's "De stella nova in pede Serpentarii" (On the New Star in Ophiuchus's Foot) would still be meaningful to future astronomers. They would also honor Kepler and Ptolemy who first described the constellation over 1700 years earlier.
It comes as no surprise that they acted as they did.
 01:18, 2005 Feb 24 (UTC)