Ophiuchians, It’s Time To Fight For Your Sign

The Sun enters Ophiuchus today. A part of this large constellation lies between the traditional zodiac constellations Scorpius and Sagittarius. I’ve outlined its official border, set in 1930, in red. Stellarium

If you were born between November 29th and December 17th you’re being sold a zodiacal bill of goods. The astrology columns will tell you you’re a Sagittarius. Don’t believe it. You’re an Ophiuchian!

Ophiuchus (oh-fee-YOO-cuss) the Serpent Bearer represents a man with the snake Serpens coiled around his shoulders. To the ancient Greeks he was the god of medicine; the snake represented healing because of its seemingly magical ability to shed its skin as if being reborn.

Constellation boundaries before 1930 were often vague and varied from atlas to atlas. Now they’re precisely mapped with borders like those separating one country from another. Credit: Urania’s Mirror

Before 1930, the Sun passed seamlessly from Scorpius to Sagittarius during its yearly trip through the zodiac constellations. Now it spends 20 days in Ophiuchus between the two. In 1925, Eugene Delporte of the Royal Observatory of Brussels proposed the need for clear, universally-accepted constellation boundaries to the International Astronomical Union (IAU).

Boundaries were vague at the time and depended upon the star atlas you were using. Understandably, this created confusion for astronomers about what was where in the sky. If you discovered a new nova, you needed to let others know if it was in Sagittarius, Scorpius or wherever. Delporte drew up boundaries along existing vertical lines of right ascension (similar to longitude but applied to the sky) and horizontal lines of declination (latitude), extending the realm of Ophiuchus between Scorpius and Sagittarius.

Now the Sun can’t help but cross into Ophiuchus on November 29th. It doesn’t depart and enter Sagittarius until December 19th. A genuine zodiac constellation if I ever saw one, but will it ever get recognized as such? That’s up to Ophiuchians. Fight for your zodiacal rights!

Now let’s go a little further and examine the 12 traditional zodiacal signs.

The 12 traditional zodiac signs are the constellations the Sun appears to pass through during Earth’s yearly orbit around our star. Astrology allots an even one month per constellation. The actual time the Sun spends in each varies according to the size of the constellation.

Your astrological sign is determined by which of the 12 constellations the sun was in on the date of your birth 2,000 years ago. 2,000 years ago? Back when Rome was a world power, the Sun really did pass through Sagittarius from late November to late December. Not anymore. Because of something called precession, it occupies that constellation from December 17th to January 20th. All the other signs are likewise off about a month. So if you’re a Leo like I am, you’re really a Cancer in the 21st century.

Precession is the slow wobble of Earth’s axis over a period of 26,000 years caused by the combined gravitational tugging of the Sun and Moon. Spin a top and watch as it slow down. You’ll notice that the axis of the top describes a little circle (wobble) in the air before eventually tipping over. The Earth’s axis describes a similar circle in the sky. Since the pole star is determined by where our axis points, it follows that the pole star will shift position and change over that long cycle. Right now, Polaris in the Little Dipper sits in the hallowed spot at which our axis points, but in 14,000 A.D., brilliant Vega will occupy the position. Due to the cyclic nature of precession, Polaris will return as the North Star again in 28,000 A.D.

The slow, cyclic wobble of Earth’s axis called precession resembles the motion of a top slowing down. The wobble causes the pole star to change and the Sun to move westward along the zodiac. Credit: Earth and Planetary Magnetism Group ETH-Zurich

The Earth’s wobble also causes the sun to drift westward along the zodiac 1.4 degrees (about three sun diameters or an index finger held at arm’s length) per century. In 2,000 years, that adds up to 28 degrees or about one zodiac constellation width. Astrology practitioners stick with the Sun’s position two millennia ago, causing a disconnect between the Sun’s true position and one’s birth sign.

I’m no believer in astrology, but I think I understand why the practice hasn’t updated astrological signs to current times. Precession never stops. In another 500 years, the Sun’s position vs. the signs will have drifted even farther. It makes sense to adopt one time and stick with it. 2,000 years ago is as good as any.

If you’d like to know what your sign should be now in the 21st century, here’s an update:

Sagittarius: Dec. 17-Jan. 20. Capricornus: Jan. 20-Feb. 16. Aquarius: Feb. 16-March 11. Pisces: March 11-April 18. Aries: April 18-May 13. Taurus: May 13-June 21. Gemini: June 21-July 20. Cancer: July 20-Aug. 10. Leo: Aug. 10-Sept. 16. Virgo: Sept. 16-Oct. 30. Libra: Oct. 30-Nov. 23. Scorpius: Nov. 23-29. Ophiuchus: Nov. 29-Dec. 17

12 Responses

  1. Bruce Brovold

    I was born on June 11th. So I guess I have now left Gemini and have become a Taurus. I know Gemini meant twin, however I do not know what Taurus means. The signs pictured above Taurus looks like a goat and a snake; is this correct? I have never believed in astrology, however, I always liked being a twin judged by my personality; it seems fitting, but not looking forward to being a goat and snake.
    Can you fill me in on what Taurus stands for? Thanks…
    You can also use my e-mail…
    Fargo, ND

  2. Troy

    I don’t think Ophiuchus should be considered part of the zodiac, do you see how the sun just barely skirts it?
    One possible reason Astrologers don’t account for precession is that when the sun is in a particular constellation the sun’s light the constellation’s stars are lost in the sun’s glare. Astrology ends up being a dead science sort of the way Latin is a dead language, doesn’t keep up to date and no one notices because the sun itself hides the problem. (My advice to astrologers:take a look up once in a while!)

          1. caralex

            Well, according to your calculations above, I’m on the ‘cusp’ between Sagittarius and Ophiuchus, being born on Dec. 17th.

      1. Troy

        There is no surprise, I disagree with how the constellations boundries are drawn. The zodiac has historical, cultural, and astronomical signficance, ignored when they drew the boundry.

        1. astrobob

          That’s true but the current boundaries have astronomical and scientific significance and in a thousand years they’ll even have cultural significance. I understand where you’re coming from though. Still, a decision had to be made or else labeling variable stars, novae and even referring to a comet’s location in a general way as in “It’s in northern Cetus”, would be a mess.

    1. Sean

      “Skirts” it implies that part of the constellation’s “territory” is more important than another. in astronomical terms, all the parts of the constellation’s territory are equal. Of course, when looking at the patterns we imagine in the stars, some areas appear more central than others. Of course, by this argument you could say that Aries also shouldn’t be part of the Zodiac, since the ecliptic is offset from the constellation’s main stars. As far as astrologers not considering precession since the background stars are lost in the sun’s glare, that was also the case 2000 years ago when the current zodiacal dates were set. so not a great explanation. of course another solution to this whole thing could be to base our calendar on the sidereal year rather than the tropical year. so, instead of the seasons remaining in the same month over the course of the precession cycle while the background stars change relative to those seasons, the seasons would occur in different months over the course of time but at least the background stars would stay consistent compared to the dates on the calendar, and the signs of the zodiac.

      1. Troy

        The zodiacal constellations actually are ancient astronomers noticing something real about the solar system, that is the ecliptic. The ecliptic as you know is the (apparent) path the sun takes (it is actually the Earth but it seems like it is the sun), but also pretty close for all the planets. So the zodiac represents a real astronomical phenomena: the plane the planets all orbit the sun. (Yes there are odd balls like Pluto and Pallas)
        I suppose you are right about “skirting” the boundary, but keep in mind the boundary was redrawn in modern times without regard to ancient astronomical tradition, which as I pointed out wasn’t completely arbitrary but elucidates the ecliptic.

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