There has been much talk about the dates of the star signs over the last few days so we thought it might be nice to have the correct dates for each zodiac sign on Sydney Observatory’s website. Most of us aren’t aware that each star sign of the zodiac (which means ‘path of the animals’) is determined by the position of the Sun at midday on the day of our birth.
You can’t see your star sign on that day of course but have to wait several months. Many astrology ‘charts’ use classical dates ie data from around the time of Claudius Ptolemy (c. 90-165) [Ptolemy was an astronomer who – only able to observe with the naked eye – believed that the Earth was the centre of the Universe.] We have to take account of the precession of the equinoxes which is a 26 thousand year wobble in the Earth’s rotation that changes the apparent position of the Sun against the background stars. So we’re now almost 10% of the way through the precession from the time of Ptolemy (which means there will be a whole lot more zodiac date changes over the next 24,000 years).
Some may argue the dates below and they are not cut and dry as constellations are simply imaginary star pictures in the night sky with only imaginary boundaries between them. The zodiac constellations are just 13 of the 88 constellations we can see in the night sky; the 13 that appear on the eclliptic, or the imaginary line along which the Sun appears to move through the sky. Yes, you heard me right, 13 – as you’ll see below.
Anyway let the fireworks begin….
In the zodiac date ranges following, the first date range in each case is the date range of the astrological sign according to the relative positions of stars, Sun and Earth today. The dates below in each case are as they would have been in Ptolemy’s time, some 1900 years ago.
On Jan 21st 2011 the Sun will cross from Sagittarius into Capricorn.
When Ptolemy was around 50 years old, 139AD, the same crossing occurred on 26th Dec including calendrical corrections.
Both of these maps were made with a great freeware program Cartes du Ciel.
21 January – to 16 February
(Was 22 December – 19 January)
17 February to 12 March
(Was 20 January – 18 February)
Currently 13 March to 19 April
(Was 19 February – 20 March)
Currently 20 April to 14 May
(Was 21 March – 19 April)
Currently 15 May to 22 June
(Was 20 April – 20 May)
Currently 22 June to 21 July
(Was 21 May – 20 June)
Currently 22 July to 11 August
(Was 21 June – 22 July)
Currently 11 August to 17 September
(Was 23 July – 22 August)
Currently 18 September to 31 October
(Was 23 August – 22 September)
Currently 1 November to 23 November
(Was 23 September – 22 October)
Currently 24 November to 30 November
(Was 23 October – 21 November)
Currently 1 December to 18 December – Ophiucus is Greek for ‘serpent-holder’ and refers to the physician who, according to Greek mythology, was said to have learnt the ability to heal people from a snake or serpent; he so successfully healed people that the numbers of people turning up in Hades dropped, so the physician was killed by the gods.
(Was not included in Ptolemy’s time)
Currently 19 December to 20 January
(Was 22 November – 21 December)
Geoff and Irma 🙂
10 responses to “Astrology is all mixed up”
Actually, ‘Tropical Zodiac’ astrologers in the West don’t use the constellations as the zodiac at all, even though some still believe they do. It’s not imaginary, it’s the Earth’s magnetic field and frequencies of inaudible “sound”. Astrology is based on the Resonance principle, which is precise and highly scientific in its basis. These frequencies do affect all biological processes on our planet, including the human brain. Astrology is the science and art of interpreting these frequencies in the same way that a musician interprets a sheet of music.
Found via Phil Plait’s “Bad Astronomy” blog. Yes, of course this article is a leg-pull, but at the same time one of the best constructed and witty critiques of astrology as a “science” I’ve ever read. Enjoy!
>Thanks for this Les.
If you’re after a great article on astrology I know none better than an article by T.G Cowling that appeared in the RAS Quarterly Journal in 1983.
This might give you some ammunition to harden your arguments.
> Another good earlier article by the same author o this subject is;
Oh, I should have said. Due to the changes in the obliquity, the Precession of the Equinoxes around the poles in not a circle but a slightly distorted wave-like epicycle, which does not return to the exact some point some 26,000 years later.
Three other points;
– The word zodiac remains unknown. It was known in Bayer’s day as the “Circle of living things, Libra is not an animal but a set of scales.
– Also astrologers called the ecliptic the “Solar Zodiac”, which is not the same connotation meant by astronomers. It is supposed to be a useful mathematical subdivision of twenty equal pieces, where astrological calculations calculate the position of the planets. In reality, the signs are not as important as the planets who radiate the mysterious powers on both individuals or humanity.
I.e. Those interested could have a look at the astrology site Lunarium, which has a reasonable explanation in how astrologers see things. (The “Astro School” section. (Here I’m not profession astrology, but for others to use the information to make more surgical attacks on their views. Also as you might clearly see, if you are prepared to “sell your soul” to Mephistopheles, you can make heaps of money!)
Comment: Whilst I strongly feel that astrology is total nonsense, and there is no “astrological radiation influencing anyone, i do also think most astronomers don’t want to understand the basic principles they hold so dear. Nor is the recognition of the underlying basic mathematics behind their created charts, whose nature go back to the time of the early astronomers trying to make sense of their often peculiar planetary motions I.e. Like retrograde motion or the frequent acceleration and de-acceleration in planetary motion. IMO, if astronomers looked at the principles they use, we could gain some vital clues about the historical ancient to modern evolution of our original understanding the planetary motion.
One comment. To be fair, the Ophiuchus constellation on the ecliptic as once considered part of Scorpius, which the astrologers, of course, call Scorpio.
Similarly, the ecliptic is also path which the planets don’t follow exactly, mostly as they are slightly inclined to the ecliptic. (Since Pluto’s demise as a planet, this solved the issue for astrologers when Pluto could cross twenty or so different constellations!)
Extra zodiacal constellations of course, in which planets can reside, include Cetus (the closest at merely 8 arcmin), Sextans (next closest) and then Orion. Cetus will official become a zodiac constellation in 5325AD (if we don’t change the constellation boundaries), then northern Orion will some 280 years later in 5505AD.
Of course the real killer will be changes in the obliquity of the ecliptic (epsilon) , which cyclically varies between about 24.5 deg and 22.5 deg. once every 55,000 years or so. [It happens to be mid-way at the moment.] This causes the line of the zodiac to be about 1 degree north or south of the present ecliptic.
In 1AD, the tilt was 23 deg 42′, differing from today’s 23 deg 26′. By about 5600 AD. the tilt will be exactly 23 degrees (and again in 19,466AD). Backwards in time, the tilt was 24 degrees in 3940 BC or BCE.
I once talked to a group of astrologers, and they knew about the issues of precession but not of the obliquity. I can assure you those astrologers were not very happy, as they realised the ecliptic not only moves forwards, but also slightly up and down!
As to why I was speaking to astrologers – well that another story for another time!
Hi Aquarius Girl. Thanks for the feedback. The problem is as I see it, if any particular idea tries to pass itself off as accurate based on mathematics or scientific principles it needs to be open to debate, testing and reform if shown to be wrong or at least lacking. As far as I can see astrology simply digs its heels in and closes its eyes. This is not how science works and without a method or reasoning we may as well play 52 up with a deck of cards and a dart. Don’t get me wrong I read my astrology book only last weekend for a giggle and could convince myself that it sounded like me, well at least the good bits 🙂 But when astronomers read items like we see where astrology is based on the 12 signs and the positions of objects we know if that is correct the positions needs to be correct and what objects count and what don’t?
I just had a look at a popular astrology website claiming us astronomers are at it again “…making mischief” and that astrologers use the first point in Aires and 12 mathematically exact zodiacs. To me this sounds like hedging ones bet. You can’t use some science and ignore the rest. What is the significance now of the first point in Airies? You could just as exactly use my front door as the starting point but they don’t. They use the stars, the positions and mass of objects but which ones?
Furthermore I read about Pluto. Is it being used as Les says above? Sometimes yes, sometimes no and that is poor science. What about Sedna and all the other dwarf planets? BTW I just did a few calculations on Pluto. The force it exerts on us at birth is about the same as a mosquito flying past 8cm away but no one worries about those do they?
All in all, astrology can be a bit of good fun but it is NOT science or scientific in anyway.
Flame suit standing by 🙂
To all the people who happen to tattoo their astrological sign …..HAHAHAHAhAAhaa
Spot on Geoff!
The other related question I want a sensible answer to is this:
Astronomers discovered Uranus (a body completely unknown to astrology for millennia) and proclaimed it a planet in the 18th century. Astrologers subsequently adopted it, ascribed attributes to it and added it to their “charts”.
Astronomers discovered and proclaimed Neptune (a body completely unknown to astrology for millennia) as a planet in the 19th century. Astrologers subsequently adopted it, ascribed attributes to it and added it to their “charts”.
Astronomers discovered Pluto (a body completely unknown to astrology for millennia) in the 20th century and astrologers subsequently adopted it, ascribed attributes to it and added it to their “charts”.
So how did astrologers react when astronomers re-classified Pluto from being a planet to dwarf planet in 2006 and add four further bodies to the list of dwarf planets, one of which is larger than Pluto (Eris) and two others virtually the same size as Pluto?
By sticking their fingers in their ears and going la la la la la … I can’t hear you … la la la la … When the zodiac is clearly, scientifically shown to have shifted due to torque induced precession of Earth’s axis of rotation their reaction is the same.
Why? Because astrologers cherry-pick from astronomy anything convenient to them and ignore everything that isn’t. The only conclusion you can reach about astrology from that is …
Guide Sydney Observatory
Contributing Editor, Australian Sky & Telescope Magazine
I think almost everyone in the astrological community agrees that nothing has changed in the zodiac. The 12 signs are a mathematically exact computation marked out from Zero Point Aries, a line through the centre of the earth. Besides, it cannot be accurate anyway…I’m an Aquarius through and through, and certainly NOT a Capricorn! 🙂 LOL