What is Sun Sign and Why It Is Important

Sun Sign, aka "Star Sign" is well known to most people thanks to the popular "horoscopes". In most cases, you can easily find it out from your date of birth. Here is a typical arangement of dates for all the twelve Sun Signs:

Aries 21 March - 20 April Libra 24 September - 23 October
Taurus 21 April - 21 May Scorpio 24 October - 22 November
Gemini 22 May - 21 June Sagittarius 23 November - 21 December
Cancer 22 June - 22 July Capricorn 22 December - 20 January
Leo 23 July - 22 August Aquarius 21 January - 19 February
Virgo 23 August - 23 September Pisces 20 February - 20 March

Astronomically, the Sun Sign is the Sign of the Zodiac in which the Sun was situated at the moment of the person's birth.

Why Sun Sign is Important

Sun Sign is a major astrological parameter for a person, and so it can be more or less important for different people depending on how much attention they are paying to astrology in their lives. However, when it comes to finding out the level of luck on a particular day, Sun Sign becomes very important as most simplified approaches to calculating the level of luck take Sun Sign in consideration.

This makes a lot of sense. From what we know about good luck now, it seems that a person is more lucky when he or she is following the path that is offered to him or her in the current incarnation. So the simplest possible answer to the question "how to be lucky?" is "just be yourself".

However, this isn't as easy answer as it seems to be. What does it mean to be oneself? What did we come to achieve or to create in this life? Sun Sign is an important component of the answer to all such questions, and this is one knowing one's Sun Sign can be really important.

What is the Problem Then?

For most people, finding out their Sun Sign is easy, and the table above is everything they need.

However, if a person was born close to a border between two signs, finding out his or her Sun Sign can be more difficult. The Sun's movement across the sky isn't perfectly aligned with human calendar, it enters any next Sign of the Zodiac on a particular moment in time, each year this moment is different and in different locations around the Earth it will map to different local times.

Claire Doyle-Beland has partially understood the problem, and in her book she offers different dates for Sun Signs on different years. This isn't an adequate solution though as the Sun doesn't enter signs at midnight, it can do it at any moment during a day. And even if it happened on some year to enter a sign exactly at midnight, New Yourk time, that same moment wouldn't be midnight in, say, Tokyo.

Let's consider a detailed example to better understand the problem.

In 1980, the Sun has entered the Sign of Aquarius on the 20th of January, at 21:49 (9:49pm) Greenwich Mean Time (GMT). This means that of those people born in London, if they were born on the 20th of January before 9:49pm, their Sun Sign was Capricorn, but after that moment it was Aquarius.

In New Yourk, the same moment in GMT was 4:49pm local time. So, despite what you see in the general table above, those born in New York after 4:49pm on the 20th of January 1980 were Aquarians, not Capricorns. And in San Francisco, the border between two signs was crossed at 1:49pm. Can you see the problem?

Now, if we take the next 1981 year, the Sun has crossed the border between Capricorn and Aquarius on the 20th of January at 3:37 (3:37am) GMT. That's 7:37pm of the 19th of January in San Francisco! So in San Francisco everyone born on January the 20th, 1980, and a significant part of those born on January the 19th, had Aquarius for their Sun Sign, not Capricorn, despite what the general table says.

Okay, but is there any way then to find out a person's true Sun Sign in border cases? Yes, there is. There are, actually, a few different ways of varying complexity, you can select the one which is the most convenient for you.

How to Find Out a Person's Sun Sign in Border cases?

First of all, you need to know the time and the place of birth. The more precisely you know the time of birth the better. If you know the time only approximately, like "in the morning", or "at night", make some reasonable approximation. Or, if you don't know the time of birth at all, take local noon in the place of birth, to minimize the error.

To find out the true Sun Sign, you have the following options:

  • You can use the Sun Sign Calculator which we created for you. This calculator is very simple but it has some limitations, see explanations below.
  • You can calculate your complete astrological birth chart using one of the available free online services, for example our Online Horoscope Calculator. You will find detailed instructions below.
  • If you are not afraid of basic math and have access to a good library, you can do all the calculations yourself. Again, the details will follow.

Sun Sign Calculator and Its Limitations

Our online Sun Sign Calculator is very precise, it uses a state-of-the-art astronomical algorithm but its limitation is that it relies on the definition of time zones provided by the computing platform.

Those time zones provided by the computing platform are good enough for most countries for the last few decades, they take in consideration Daylight Saving Time and other changes. However, the history of time zones around the globe is too complicated, and the widely available time zone definitions don't take into account all the peculiarities of that history. For example, they don't reflect the fact that in the 1950s no Daylight Saving Time was used in Florida, and so depending on the date and time of birth the Sun Sign Calculator might produce a wrong result.

Also, some countries, like Russia, keep changing their time zones every now and then. It will take a while before those changes will be reflected by software platforms around the world, and so the Sun Sign Calculator won't be reliable for those born in the last few years in Russia.

If there is any reason why you believe the Sun Sign Calculator might not work well for you, consider the other available options.

Using Online Horoscope Calculator

A complete astrological chart (horoscope proper) is a scematic picture of the sky at the moment of birth, and it has all the details in it, including the precise position of the Sun in a Sign of the Zodiac. Previously, you had to purchase an expensive software to calculate such a chart, or to do all the nontrivial calculations yourself using various tables, but nowadays there are free online services that can calculate a precise horoscope for you. We are offering one of such services as an Online Horoscope (Birth Chart) Calculator.

These services are more precise than the Sun Sign Calculator mentioned above because they make use of ACS Atlas, the best available knowledge base regarding geographical locations and their time zones. As a result, a birth chart created an online service will give a more precise information about the Sun Sign than the Sun Sign Calculator for those born more than a few decades ago.

However, take into account that depending on how recently a particular copy of ACS Atlas was updated, online services might not have the most up-to-date time zone changes for some countries.

Here is how to find out your Sun Sign using our Online Horoscope Calculator.

Enter the date of birth and the time of birth in the form, but be careful not to tick the Time Unknown checkbox if you know the time.

Start typing the name of the place of birth into the City of Birth text box, and a list of available options will appear. Select the place you need in the list. Here is a result of data entry for 10:30 am, January 20th, 1981, Can Francisco, California:

Birth data entry

Press the Next button, and you will see the chart:

A chart for 01/20/1981, San Francisco

Find the orange symbol of the Sun (a circle with a dot in it) and hover your mouse over it. The information box above will tell you: "Sun 0° 38' Aquarius", so you will know that the Sun Sign for a person born at this moment in San Francisco is Aquarius.

There are other online horoscope calculation services which you can use as well, here is a couple of them:

Doing It by Hand

To find an exact moment when the Sun enters a sign, you can use one of the available Ephemeris books, such as The American Ephemeris. To find the most precise available information about time zones and time changes around the world, you can use The American Atlasor The International Atlas published by ACS Publications.

Then it's just a matter of simple arithmetical calculations, to figure out whether a person was born before the Sun has changed the sign or after that.

If you need more information on this, please let us know.