Every few years, the nonsense about the "13th sign" comes up again and Astrologers sigh, shake their heads and wait for the panicky questions from people who are worried that their "sign has changed." Nasa do this periodically to try and discredit Astrology, claiming Astrologers "ignore" certain constellations.
The zodiac (Greek zodiakos, meaning "circle of animals." wheel has 12 sections (spanning the ecliptic) and they are not aligned with the constellations, but based on the seasonal changes - the equinoxes, solstices and the periods in-between. Western or tropical astrology was not created to be in alignment with the constellations. The tropical zodiac is fixed to the seasons and does not move.
It is always people with zero working knowledge with astrology who continue to perpetuate this myth. Ptolemy was very clear about this issue in his famous astrological work, the "tetrabiblos." For example, the properties of tropical zodiac sign of Cancer are vastly different than those of the constellation of Cancer. Some of the stars within the constellation are said to have the nature of Mars and Saturn.
All astrologers, both tropical and sidereal are aware of the precession of the equinoxes and the Tropical or Western zodiac is independent of the constellations so not affected by the shift. The Greeks didn't use the constellations to measure the positions of the planets because then the ecliptic wouldn't have been divided into equal portions.
The Greeks knew about the equinox precessions but it didn't matter as their astrology at the time was based entirely on the path of the sun. Sidereal astrology takes into consideration the precession of the equinoxes, not Tropical or Western astrology as tropical gets its interpretation of the signs from the seasons, not the fixed stars.
Any astrology chart cast in Greek times would still be totally accurate today as the charts aren't affected by precession. The confusion comes from the 12 Tropical signs sharing the same names as the constellations, and Nasa and other critics of astrology use this as a way to attack Astrology but they, and annoying commenters on Youtube, get the Tropical system totally wrong. As I said before, the Greeks didn't use the constellations in this way, in their zodiac system.
Tropical astrology divides the zodiac wheel into 30 degree sections. Scorpio is the 8th sign and this makes senses from a numerological and metaphysical perspective. Scorpio is the sign connected with death, and during Scorpio season, the natural world is dying and the leaves and flowers are rotting. The 30 degree divisions in tropical are the different points within the seasonal cycle. So the difference lies between Tropical and Sidereal astrology.
Western astrologers use the fixed, tropical zodiac. Some western astrologers, like myself, also use the fixed stars and in this case the sidereal zodiac is used. All of the ancient, Western astrologers used both tropical and sidereal Zodiacs as they are used for different aspects of astrology.
I use both the parans method which is the original method that the mesopotamians worked with, and the Ptolemaic calculations using the sidereal Zodiac.
Ophiuchus does not feature in the tropical zodiac as it is a constellation. I cannot, for the life of me, understand why people are choosing to ignore the Sun and the impact that it has on all of our lives which is what tropical is based on. In my opinion, this is due to the subversion of astrology - organisations like NASA rely on your ignorance to gatekeep astrology.
The western zodiac wheel is based on the seasons and equinoxes. In fact, it is essentially a solar calendar that reflects the polytheistic wheel of the year on earth.
I also encourage readers to look at the following link where the author proves that the ancient Brahmins of India used a tropical Zodiac for planets and sidereal for stars, like famous Western astrologers such as Ptolemy. https://madhivanan.in/saptarishis-used-tropical-zodiac/
In fact, all ancients astrologers used both Zodiacs within their practices.
P.S - Western Astrologers are aware that there has always been a constellation named Ophiuchus.
P.P.S Tabloids, Nasa and women's magazines aren't the best places to find real information on Astrology, which has been studied and practiced for over 5,000 years.