I have restated JHunterJ s version to use well defined astronomical terms JHunterJ s version was unclear because There is no official definition of zodiacal longitude If we take zodiacal longitude to mean celestial longitude then every celestial object and constellation has a range of celestial longitude so the statement becomes meaningless As far as I can tell modern astronomers no longer offer precise definitions of sign of the zodiac and various media use the term in many different ways Thus the term is not well enough defined to decide of it is a mistake to describe Ophiuchus as the 13th sign of the zodiac