Steve, of course I do not understand astrology, I would not have initiated this topic otherwise, whose aim is to try and understand reconcile classical astrology and logic, if not science.
It is all too evident that most astronomers and physicist still do not understand that the influence of the stars is not physical. It is not the light or the electromagnetic radiations, it is some other kind of influence they do not understand nor want to make any effort to understand.
Your mentioning tropical astrology prompted a research which has spawned some interesting concept. For example, the 12 constellations are just a memento, a benchmark, a conventional way to indicate 12 segments of the ecliptic of the same angular width. This is most important since it effectively rebuts all fo NASA criticism. The 12 signs system is just a convention to indicate specific segments or sectors of astral influence.
What surprises me though, is that there is not an explanation of such a simple concept in the NASA site nor in the Wiki voice I indicated. OK, it is not physical science but the logic Beyond that should be considered and accepted.
The classical zodiac was introduced in the neo-Babylonian period (around the seventh to the sixth century BCE). At the time, the precession of the equinoxes had not been discovered. Classical Hellenistic astrology consequently developed without consideration of the effects of precession. The discovery of the precession of the equinoxes, is attributed to Hipparchus, a Greek astronomer active in the later Hellenistic period (ca. 130 BCE).
Ptolemy, writing some 250 years after Hipparchus, was thus aware of the effects of precession. He opted for a definition of the zodiac based on the point of the vernal equinox, i.e., the tropical system. While Ptolemy noted that Ophiuchus is in contact with the ecliptic, he was aware that the 12 signs were just conventional names for 30-degree segments.
