Since the direction of Vernal Equinox lies in the Pisces constellation, why is its symbol Aries? Shouldn't it be ♓ ?

Is this a historical anachronism, only invalidated by axial precession of Earth?

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    $\begingroup$ Is this an astronomy or astrology question? $\endgroup$ – Sir Cumference Sep 12 '16 at 13:14
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    $\begingroup$ @SirCumference The astronomical symbols are sometimes, if rarely, used in astronomy. This question does not necessitate discussion of astrological practice per se, except as it pertains to the history of astronomy. $\endgroup$ – called2voyage Sep 12 '16 at 13:48
  • $\begingroup$ Explained in en.m.wikipedia.org/wiki/First_Point_of_Aries $\endgroup$ – ProfRob Sep 12 '16 at 16:54
  • $\begingroup$ @SirCumference: I found the symbol on the wikipedia article on orbital elements, then found it a couple times in related context (orbits of artificial satellites). I would have asked on Space Exploration, but I know the rocket scientists "inherited" it from astronomers, and this being a historical question, this is "closer to the origin". $\endgroup$ – SF. Sep 12 '16 at 17:13
  • $\begingroup$ @SirCumference I think it is astronomy, the terminology of which is very much shaped by its historical development. Even today new terms are minted which will soon become legacy inheritance. I think it is useful as a reminder that frontier astronomy is to fumble in the dark. Larger mirrors collecting even more light have thus far only moved that frontier. Astronomy gradually transitioned from a tool of astrology, into a real science of its own during the 17th century. Giovanni Cassini was one of the converters. One can't learn the difference unless one looks up. $\endgroup$ – LocalFluff Sep 14 '16 at 15:39

As Wikipedia explains in the article on the Zodiac, the Zodiac was originally developed with the assumption of fixed equinoxes. It is assumed this is because the Babylonians who developed the Zodiac were unaware of the precession of the equinoxes. At that time, about 2500 years ago, the vernal equinox did in fact lie in Aries. For this reason, in astrology, that time is referred to as "the Age of Aries".

Of course, in modern times these astrological concepts are scarcely important to astronomy, and in the few cases where the astronomical symbol for the vernal equinox is used, it is more practical to have a fixed symbol than a changing one.


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