minotaur
Some of the signs of the zodiac have different start and end dates, depending on who you ask.
Why?
Is there one set of dates that is most accepted?
Why?
Is there one set of dates that is most accepted?
a very basic zodiac sign question
Minderwiz
It's actually a very perceptive question. I think I've touched on it before in different questions but it's good to get a direct question, as a lot of people take the dates quoted in their favourite horoscope column to be the definitive ones.
The short answer is there isn't a 'correct' set of dates.
I spent nearly thirty years believing that I was a 'Scorpio' because horoscope columns quoted 23rd October as the beginning of Scorpio. What they don't tell you is that this hides some significant year on year variation.
I'll give the reasoning in for this, but if you don't really care why it happens you can skip the next bit and simply accept that the year isn't quite as constant as you thought it was, which in turn leads to variations in the time when the Sun enters a sign. Those variations are not reflected in horoscope columns stated dates.
Simplified explanation - you can ignore this if you don't like numbers or technical stuff
The reason for this is that the Earth's orbit around the Sun is not completed in exactly 365 days or even 365.25 days. Indeed the definition of a year is not quite as simple as you would think. Astronomically there are two ways that it could be measured. The first is when the Sun appears against a fixed point in space, usually a notable star. The time between two consecutive conjunctions with this star could be defined as a year. This is called a sidereal year (from the Latin sidus meaning a star.) The average length of the year on this measurement is 365 days 6 hours 9 minutes 9.7 seconds.
The second way it could be done is to measure the Sun relative to the seasons of the year. The March equinox is usually taken as the start of Spring in the Northern Hemisphere and the average length of time between two March equinoxes is 365 days, 5 hours, 48 minutes and 45 seconds. Note these two measures differ by over twenty minutes.
You will notice that in both cases I cited the average length of a year. In fact there are small variations year on year due to perturbations and nutations in the Earth's orbit - which basically means there are small wobbles, rather like a spinning top.
To try and keep both sideral and seasonal (or tropical) years in sync, we have a system of leap days added to the calendar. Without them we would literally risk Christmas eventually coming in July. The leap days don't and can't eliminate the year on year variations but these balance out over time.
In Western Astrology we use the March equinox as defining the first point of Aries (0 Aries) which in turn defines the rest of the zodiac
Iif you look at the March equinox, over a 10 year period from 2010 to 2020 it will (or has) occured on March 20th each year, but the actual hour varies between 03:50 and 23:21 - that's a range of virtually 19.5 hours.
This variation isn't random. You will find that the time of the ingress increases year on year but this is brought back every four years by the additional leap day. So 2012 was a leap year and the ingress occured at 05:14, in 2013 it was 11:02, in 2014 16:57 and this year it was 22:45 but next year is a leap year so in 2016 it will be 04:30.
See the attached table for this and the other three cardinal points, the June Solstice (0 Cancer) The September Equinox (0 Libra) and the December Solstice (0 Capricorn
The 2016 equinox is 44 minutes earlier than the 2012 equinox and the 2020 equinox will be another 40 minutes earlier at 03:50. That means that even with the leap day, our calendar is drifting off the equinox at the rate of 10 minutes a year (approximately). That's an hour ever six years or a day every 144 years. That too can be dealt with through calendar/time adjustments.
The times and dates quoted are measured in Universal Time (GMT). For countries that are using daylight saving on 20 March there will be an hour's difference and for countries East or West of Greenwich, it's possible that the equinox will occur on the 21th March, 20th March or the 19 March, depending on their longitudes and time zones.
Safe reading for non mathematicians
The exact time of the March Equinox can vary. Why is the March Equinox important? Because it marks the entry of the Sun into Aries. Indeed Western Astrology defines 0 degrees Aries as the March Equinox.
For other signs, that variation in the Solar ingress can easily encompass two dates even at the same longitude. The attached table shows that the June Solstice (0 Cancer), the September Equinox (0 Libra) and the December Solstice (0 Capricorn) will occur on either of two dates over this ten year period. The same holds for the rest of the signs.
That's why, whilst most Scorpio ingresses are on 23rd October (UT), it can and does sometimes ingress on the 24th, though usually in the early hours and I was born in the very early hours of 24th.
Unfortunately, horoscope columns rarely if ever adjust each year for the actual ingresses into signs. Instead they keep the same standard ones year on year.
If you are born on or near (next day or previous day) one of the ingresses as listed on the horoscope column, it can be dangerous to assume that you have to be that Sun sign.
If you were born in the year preceding a leap year, then there's a chance you were born in the preceding sign from that given by the horoscope even if your were born on the following day, especially if you were born in the early morning.
If you were born in a leap year, on the day before that given by the horoscope , you might well be in that sign, especially if you were born late in the day.
In both cases, use one of the web based chart calculators, such as astro.com to check your actual birth chart. Even if you only have a rough time of birth, it may still be worth it, because if you know you were born before lunch and the ingress for that year is early evening, then your Sun sign is the previous one. In my case it turned out I was Libra, not Scorpio.
The short answer is there isn't a 'correct' set of dates.
I spent nearly thirty years believing that I was a 'Scorpio' because horoscope columns quoted 23rd October as the beginning of Scorpio. What they don't tell you is that this hides some significant year on year variation.
I'll give the reasoning in for this, but if you don't really care why it happens you can skip the next bit and simply accept that the year isn't quite as constant as you thought it was, which in turn leads to variations in the time when the Sun enters a sign. Those variations are not reflected in horoscope columns stated dates.
Simplified explanation - you can ignore this if you don't like numbers or technical stuff
The reason for this is that the Earth's orbit around the Sun is not completed in exactly 365 days or even 365.25 days. Indeed the definition of a year is not quite as simple as you would think. Astronomically there are two ways that it could be measured. The first is when the Sun appears against a fixed point in space, usually a notable star. The time between two consecutive conjunctions with this star could be defined as a year. This is called a sidereal year (from the Latin sidus meaning a star.) The average length of the year on this measurement is 365 days 6 hours 9 minutes 9.7 seconds.
The second way it could be done is to measure the Sun relative to the seasons of the year. The March equinox is usually taken as the start of Spring in the Northern Hemisphere and the average length of time between two March equinoxes is 365 days, 5 hours, 48 minutes and 45 seconds. Note these two measures differ by over twenty minutes.
You will notice that in both cases I cited the average length of a year. In fact there are small variations year on year due to perturbations and nutations in the Earth's orbit - which basically means there are small wobbles, rather like a spinning top.
To try and keep both sideral and seasonal (or tropical) years in sync, we have a system of leap days added to the calendar. Without them we would literally risk Christmas eventually coming in July. The leap days don't and can't eliminate the year on year variations but these balance out over time.
In Western Astrology we use the March equinox as defining the first point of Aries (0 Aries) which in turn defines the rest of the zodiac
Iif you look at the March equinox, over a 10 year period from 2010 to 2020 it will (or has) occured on March 20th each year, but the actual hour varies between 03:50 and 23:21 - that's a range of virtually 19.5 hours.
This variation isn't random. You will find that the time of the ingress increases year on year but this is brought back every four years by the additional leap day. So 2012 was a leap year and the ingress occured at 05:14, in 2013 it was 11:02, in 2014 16:57 and this year it was 22:45 but next year is a leap year so in 2016 it will be 04:30.
See the attached table for this and the other three cardinal points, the June Solstice (0 Cancer) The September Equinox (0 Libra) and the December Solstice (0 Capricorn
The 2016 equinox is 44 minutes earlier than the 2012 equinox and the 2020 equinox will be another 40 minutes earlier at 03:50. That means that even with the leap day, our calendar is drifting off the equinox at the rate of 10 minutes a year (approximately). That's an hour ever six years or a day every 144 years. That too can be dealt with through calendar/time adjustments.
The times and dates quoted are measured in Universal Time (GMT). For countries that are using daylight saving on 20 March there will be an hour's difference and for countries East or West of Greenwich, it's possible that the equinox will occur on the 21th March, 20th March or the 19 March, depending on their longitudes and time zones.
Safe reading for non mathematicians
The exact time of the March Equinox can vary. Why is the March Equinox important? Because it marks the entry of the Sun into Aries. Indeed Western Astrology defines 0 degrees Aries as the March Equinox.
For other signs, that variation in the Solar ingress can easily encompass two dates even at the same longitude. The attached table shows that the June Solstice (0 Cancer), the September Equinox (0 Libra) and the December Solstice (0 Capricorn) will occur on either of two dates over this ten year period. The same holds for the rest of the signs.
That's why, whilst most Scorpio ingresses are on 23rd October (UT), it can and does sometimes ingress on the 24th, though usually in the early hours and I was born in the very early hours of 24th.
Unfortunately, horoscope columns rarely if ever adjust each year for the actual ingresses into signs. Instead they keep the same standard ones year on year.
If you are born on or near (next day or previous day) one of the ingresses as listed on the horoscope column, it can be dangerous to assume that you have to be that Sun sign.
If you were born in the year preceding a leap year, then there's a chance you were born in the preceding sign from that given by the horoscope even if your were born on the following day, especially if you were born in the early morning.
If you were born in a leap year, on the day before that given by the horoscope , you might well be in that sign, especially if you were born late in the day.
In both cases, use one of the web based chart calculators, such as astro.com to check your actual birth chart. Even if you only have a rough time of birth, it may still be worth it, because if you know you were born before lunch and the ingress for that year is early evening, then your Sun sign is the previous one. In my case it turned out I was Libra, not Scorpio.
Attachments
minotaur
Thank you. That was quite complete and understandable. I appreciate the work you did on this answer.
If I am working with just sun signs and no chart is there a set of dates that is "right" more often than other sets of dates?
If I am working with just sun signs and no chart is there a set of dates that is "right" more often than other sets of dates?
Minderwiz
Sadly no. If you look at the attachment and pick out the September Equinox, you will find a 6:5 split for 23 September. If you took that date as the start of Libra, in nearly half the years, Libra would actually have started the day before. if you took the 22nd then it would be wrong in just over half the years.
That's the most extreme, the March Equinox was always on 20th. But do the same for every sign and you'll find that taking the most usual dates for each sign overall, may be highly misleading in a particular year, giving several wrong dates.
That's why Astrologers never use a horoscope type list. Instead they use the solar ingresses for specific years.
If knowing the dates for specific years isn't necessary then taking the most frequent date will work but contains some element of error. If you need to know the situation in specific years then you will need a list of solar ingresses.
http://www.moontracks.com/sun_solar_ingress.html
provides a table for this year, 2016 and 2017. The following point needs to be allowed for though.
Shifting the longitude of your location away from 0 degrees, will have an effect on the dates. Move to the USA and in some years the March Equinox might shift back into 19th March. It's also quite possible, it could be the 20th March on the East Coast but 19th March on the West Coast and the time zone in which the date changes won't always be the same.
That's the most extreme, the March Equinox was always on 20th. But do the same for every sign and you'll find that taking the most usual dates for each sign overall, may be highly misleading in a particular year, giving several wrong dates.
That's why Astrologers never use a horoscope type list. Instead they use the solar ingresses for specific years.
If knowing the dates for specific years isn't necessary then taking the most frequent date will work but contains some element of error. If you need to know the situation in specific years then you will need a list of solar ingresses.
http://www.moontracks.com/sun_solar_ingress.html
provides a table for this year, 2016 and 2017. The following point needs to be allowed for though.
Shifting the longitude of your location away from 0 degrees, will have an effect on the dates. Move to the USA and in some years the March Equinox might shift back into 19th March. It's also quite possible, it could be the 20th March on the East Coast but 19th March on the West Coast and the time zone in which the date changes won't always be the same.
minotaur
Thank you very much.
