We all agree that there are twelve zodiac signs. It’s true that the ancient Babylonians greedily used eighteen, but for the last couple of millennia, we’ve been satisfied with twelve. The antiquity of the concept is shown by Virgil, the Latin poet, writing in his Georgics in 29 BCE about the stars withdrawing to make space for Caesar as a thirteen sign of the zodiac. The idea of a thirteenth sign was a joke two thousand years ago.


So where did we get the idea that there are thirteen signs in the zodiac?


The thirteen sign issue isn’t a story whose origin is lost in the mists of time. We know exactly who was responsible—the American science fiction writer John Sladek.


Text Box:  Sladek, known for his satirical and surrealistic novels, spent the 1960s in London and was part of the New Wave that began in 1964 when Michael Moorcock took over as editor of the science fiction magazine New Worlds. Moorcock liked to publish unusual literary stories and New Worlds sought to distance itself from traditional science fiction, breaking literary taboos. New Wave writers saw themselves as part of a general literary tradition and mocked the traditions of pulp science fiction. (The New Wave also had a political subtext with many of its writers coming from Marxist and socialist political traditions.)


Sladek’s most famous novel The Müller-Fokker Effect appeared in 1971. It was the story of how an attempt to preserve human personality on tape goes awry—although many readers were simply entranced by its title. Sladek was also known for his parodies of other science fiction writers.


While science fiction was redefining itself as literature, a new type of writing was becoming popular in the mass market—pseudo-science as scientific fact. The most renowned of these authors was the Erick von Däniken who produced a number of books about extra-terrestrial influence on human culture since prehistoric times. Däniken is one of the key figures responsible for popularising ancient astronaut theories. In 1967, while von Däniken was in prison after being convicted for embezzlement, forgery, and tax evasion, his first book Chariots of the Gods was published. He wrote his second book Gods from Outer Space while still in prison.


Sladek wrote a scathing attack on von Däniken and his work in 1969. By this time, Moorcock had published Sladek’s work in New Worlds, and was planning to write a book on irrational beliefs. When Moorcock realised he was never likely to write that book, he turned the title and some of his research over to Sladek. Sladek was hooked. He became a born again sceptic and wrote The New Apocrypha: A Guide to Strange Sciences and Occult Beliefs (1973).


Initially, Sladek had hoped to find something in parapsychology but was frustrated by all the badly conducted experiments and outright fraud he encountered. He couldn’t resist poking fun at every topic he covered. For example, the chapter on flying saucer cults was entitled ‘Will U kindly FO?’ Apocrypha covered a huge range of material, including Nostradamus, psychic detectives, eternal motion machines, secret codes that prove that Bacon wrote Shakespeare, Noah’s Ark—and Erich von Däniken. Sympathy for Däniken was in short supply and Sladek continued to parody him, for example, in his 1974 short story ‘Space Shoes of the Gods’.


A ruined edifice in Peru bears a weird inscription: two horizontal lines crossed by two vertical lines. In other words, the figure for tic-tac-toe, a game played by the latest giant computers. Likewise the Ankara Museum displays clay tablets pierced with holes—the same holes used in modern BM cards.

Despite the tone, Sladek’s expositions were impressively researched, and he let his subjects demolish, themselves. Apocrypha attacked many who Sladek viewed as false gurus, including Immanuel Velikovsky and L. Ron Hubbard, the founder of scientology. The Church of Scientology threatened legal action as Sladek quoted an article from Queen magazine without knowing they’d already successfully sued for libel over it. In lieu of damages, they had the section on scientology altered in the British paperback edition of Sladek’s book.


Responses to Apocrypha mixed approval and anguish, agreeing that most targets were junk science, with one exception, that exception varying each time.


Sladek had become fascinated with unorthodoxy and the occult, as well as its adherents. The year following Apocrypha’s publication was filled with stories of Uri Geller’s spoon bending, Koestler’s coincidence theories and the Berlitz triangle. The American Humanist magazine of September 1975 carried a statement signed by 186 leading scientists objecting to astrology under the name of ‘Objections to Astrology’ which ensured that astrology was a prime target.


Two years after the Manifesto appeared, Sladek published Arachne Rising: The Thirteenth Sign of the Zodiac under the name of James Vogh. Arachne Rising claimed to be an account of a thirteenth sign of the zodiac being suppressed by the scientific establishment. Sladek offered impressively researched historical, mythical, literary, and numerological evidence for the suppressed sign of Arachne the spider.



The idea of additional zodiac signs wasn’t new. Indeed, in 1970 Stephen Schmidt suggested a fourteen-sign zodiac including Ophiuchus and Cetus as signs in his book Astrology 14.  However, Sladek’s book reached a much larger audience.


There may have been a more personal reason for Sladek’s astrological spoof. Owing to a discrepancy between hospital and state records, Sladek didn’t know whether he was born in October 1937 (as suggested by hospital records) or on 15 December 1937 (according to Iowa State records). He chose to celebrate his birthday on the latter date.


To fit Arachne into the zodiac, Sladek divided it into thirteen and inserted Arachne between 25° 23’ Taurus and 23° 5’ Gemini. He included statistics that showed that people born under Arachne (13 May to 9 June) were usually psychic. This led to enthusiastic mail from Arachnoid readers who claimed they’d known this all along.


Sladek’s thirteenth sign was identified roughly with the constellation Auriga, and supposedly took more account of the Moon’s influence. He argued that Auriga was the thirteenth sign in the lunar zodiac used by the Druids amongst others and that Auriga was widely known as a zodiac sign in ancient times but had been suppressed after the Middle Ages because of its psychic lunar connections. In addition, the Church opposed the use of Arachne due to its Celtic ancestry. (The idea of an ancient Celtic zodiac reappeared in 1992 with Helen Patterson’s book The Celtic Lunar Zodiac.)


Alongside interpretations of charts of people such as Uri Geller, Sladek included astrological case histories for Cassandra Knye, the name under which Sladek and Thomas Disch had published spoof Gothic novels, and James Colvin, a New Worlds house pseudonym used by Michael Moorcock.

The book read like, and quoted, serious astrological and historical sources. Perhaps because not enough astrologers read science fiction, it was accepted as a serious astrological text—if a little peculiar, but any astrologer knows that there is no shortage of peculiar astrological texts. The book was republished in 1979 under the new title of The Thirteenth Zodiac: The Sign of Arachne.


Sladek later announced that the whole thing had been a hoax. That did little to stem the enthusiasm of some astrologers, who continued to use the ‘new sign’. He claimed to have been surprised that people took the book so seriously. Perhaps it was his surprise that persuaded him to write the follow-up volume The Cosmic Factor in 1978 and (under the name of Richard A Tilms) Judgment of Jupiter in 1980.


In the greater scheme of things, Sladek’s books caused hardly a ripple. It would be another twenty years before an astronomer came into the picture to introduce the idea of a missing zodiac sign.

In 1995, Dr Jacqueline Mitton (Public Relations Officer of the Royal Astronomical Society) acted as a consultant to the BBC and appeared in the third episode of the television series about astronomy Heavenly Bodies. While filming, Mitton mentioned that the zodiac contained a thirteenth constellation and pointed out that there was a difference between her astrological Sun sign as usually given and the true position of the Sun on her birthday. The first episode of Heavenly Bodies was scheduled for broadcast on Sunday 22 January 1995. The BBC sent out publicity material, and it landed on the desk of Roger Highfield, the science editor of the Daily Telegraph.


Highfield contacted Mitton to talk to her about her views on astrology and the astronomy behind them. These were reported in an article published on 20 January which included a diagram illustrating the difference between the traditional zodiac divided into twelve equal signs and an ‘astronomically correct’ zodiac based on the true path of the Sun through the sky.


Between 2,000 and 3,000 years ago the dates on which the sun appeared in the different constellations were worked out by apportioning one twelfth of the sky to each constellation. Those dates are still used by astrologers for their predictions. Because the stars are only visible during the night most people have to take the astrologers’ word for it when they talk about being ‘in’ a particular star sign: that is when the sun is in front of a particular constellation. Unfortunately for astrologers, the constellations cover different sized areas of the sky, according to the International Astronomical Union. ‘Some constellations cover much bigger areas than others,’ said Dr. Mitton. This means that each zodiac sign should, in reality, cover a different number of days.’ 


Mitton was referring to the International Astronomical Union redrawing the boundaries of the constellations in 1930 and including a thirteenth constellation along the ecliptic. According to the official modern constellation boundaries astronomers use, the Sun now passes through thirteen constellations. The thirteenth constellation is Ophiuchus the Serpent Bearer and the Sun is in front of its stars from approximately 30 November to 17 December. (Ophiuchus is one of the original Ptolemaic constellations and appears in the Almagest.)


The following day the rest of the press followed suit with their own stories and the Royal Astronomical Society began to field calls from all over the world about the new zodiac sign. Alert thirteenth sign hunters remembered that Sladek had pointed out the position of Ophiuchus on the zodiac belt in Arachne)


Articles appeared in astrological publications, and (for a short time) there was excited discussion. Most astrologers rubbished the idea saying that the zodiac and the constellations aren’t and had never been the same so there was no reason for any change. A few astrologers were tempted by the new sign because of the association with the thirteen lunar months. A minority looked to the myth of Ophiuchus so that they could incorporate its meaning into their work.


With almost unseemly haste, Walter Berg’s The Thirteen Signs of the Zodiac was published on 22 May 1995. And in the original version of this article written in 2004, I pointed out that the whole idea had then been quietly forgotten.


I was wrong.


In 2011 a post on NASA’s website pointed out that the Babylonians had excluded Ophiuchus from the zodiac. The text appeared on an educational site for children called ‘The Space Place’. In 2016 Cosmopolitan (UK edition) ran a story about the thirteenth sign that went viral.  It stated that NASA had researched zodiac signs and re-drafted the zodiac to include Ophiuchus, NASA was forced to release a press statement. It didn’t matter—the zodiac had changed.

NASA has just gone and dropped the mother of all bombshells to announce there’s another zodiac sign and we’ve basically been living our lives under false pretenses this whole time. Way to go NASA, ruin our lives why don’t you?  


The story about the zodiac being ‘wrong’ and how we need to take notice of a thirteenth sign now appears every summer. (Why has never been satisfactorily explained.)


And every year astrologers get indignant all over Facebook.




Elle, 18 September 2016 [accessed 18 August 2020].