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Author: Alison Price   –   Published: June 2024

Let’s Talk About Birth Data

In astrology the actual chart is the core of an interpretation.

For every reading you absolutely require a chart.

When you cast a birth chart for someone you do need a few bits of information.

And specifically, you require three important facts to cast any chart.

3 Components

The three core pieces of information you need are:

  • The birth date.
  • The birthplace.
  • The birth time.

Of course you could always use other input as well such as, why they came to you in the first place and what the focus of the consultation should be, but those details are not essential to cast the actual chart.

Quick Sidebars

I’ve highlighted two asides here for you to ponder which might throw some light on this topic.

I don’t want to go into detail on either point in this newsletter.

Please let me know if you’d be interested in a deeper look later.

Sidebar 1: Birth Data Ratings

Birth data is categorized on the Rodden Rating system as follows.

AA = Accurate accurate: From birth certificate or record – written down and in hand.

A = Accurate: From memory, family legend or hearsay – spoken or word of mouth.

B = Biographical: From autobiography or biography – second hand.

C = Caution: From conflicting sources.

DD = Dirty Data: Don’t use.

X = No time: Date only with no birthtime.

XX  = Very insecure.

I prefer to only cast charts with an “AA” or “A” rating.

Of course you can cast charts with weaker data, but each chart you prepare takes up your time and your energy.

It is a lot of work and you still may not be correct.

Sidebar 2: Birth Time as Given

In astrological circles, there is a school of thought which believes that you can reliably cast charts using “birth time as given”.

Birth time as given is criteria used in manual chart calculations mainly, but can be with a computer.

It really means that any information which the client provides you, the astrologer, will work for them.

The individual will resonate with the resulting chart, even if it is not exact.

The fact that they gave you some particular birth data is embedded in their psyche and becomes a part of who they are.

It can be related to a Freudian slip.

I’ll not debate this idea now.

Let’s have a closer look at the 3 essential facts required for a birth chart calculation.

1. Birth Date

The birth date is usually available.

Just about everyone knows their birth date.

But just about does not mean all…

Date of Birth

In my many years as an astrologer, I’ve only come across three people who were not sure of their birth date.

This was back in Africa where things were not written down.

Un-noted birth dates were especially the case for mothers who had home deliveries in remote villages.

Year of Birth

But it’s not just their birth dates that people don’t know.

Amazingly there was one woman who did not know her year of birth.

It seems her mother could not recall.

However, she did know the day and month.

But in the main you will get their full birth data including day, month and year. Brilliant!

Historical People

Another situation occurs when you work with historical charts.

It is often impossible to get a good birth date for very old charts.

Anyone from history or people born 500 plus years ago, when records were few and far between, frequently do not have a time and sometimes do not have a date either.

But for most people alive today, and I’m assuming these are the charts you are working on, will provide you with the birth date.


2. Birth Place

Typically, the birth place is readily available.

People do tend to know where they were born.

As another aside to this, let me tell you that the birth certificate is not always correct either.

I’ve had a client whose official birth certificate, in hand, was written with a city in England, but he was actually born in Kenya.

His parents only registered his birth at six weeks old when they returned to their home country.

Tricky, tricky.

In Flight

Even people born on airplanes know whereabouts they were on the flight at the time.

This doesn’t happen much anymore as the airlines are stricter about pregnant women boarding in the first place, but you do still get this situation for people past their second Saturn return.

Interestingly, these folk seem to be able to claim citizenship from both the departure and the arrival country.

City Center

I have experienced a situation where someone born in a big city, like say Mexico City or Tokyo, could gently tweak the birthplace.

Born in a huge city, and with a firm birth time, their calculated Ascendant was within a whisker of a sign cusp.

This meant their Ascendant sign could be one of two choices.

The person, although their birth time and date were good, felt the returned Ascendant was off.

In this instance, I zoomed into the specific birth hospital location.

By digging into their information and using a map, I found the actual nursing home building where they were born.

I extracted the longitude and latitude and then manually input these coordinates into my astrological software to firm up the Ascendant.

Usually, all big cities have their geo-coordinates set at the town hall or the post office.

Someone born in a hospital in a big city could be up to 50km away from the actual city coordinates which pop up in astrology software.

Looking back now, I wonder “Who has time for this sort of deep dive?” but yes, I did.

I did it all back then.

3 Birth Time

The third piece of birth data required is the birth time.

Noon Chart

As the first step, if my client has no birth time, I will cast the noon chart.

A noon chart is created with the birth time set at 12 noon.

This is right in the middle of the day.

The idea is that with a noon chart you can only be 12 hours out.

And let’s face it 12 hours is still huge, but it is better than being 24 hours out.

With the noon chart you have to ignore the angles and house cusps.

Although you can be pretty confident on lots of the planets in their signs and many of the aspects will hold up.

Noon Chart Exceptions

Of course, there are a couple of exceptions to being sure of a planet’s sign with a noon chart.

Exception 1: Sign Cusp Planets

Any planet, especially the Sun, Mercury, Venus or Mars, which is close to a sign cusp at 0 degrees or 29 degrees of any sign, could potentially change signs that day.

Planets do not conveniently change signs at midnight.

The sign ingress may occur either before noon or after noon.

Because in a noon chart we don’t have a firm birth time, you can’t say for sure which sign any planet that is placed on a sign cusp was in.

And note that this planet-on-sign-cusp can be any of the planets which might change signs, not just the personal planets.

Either way, the outer ones move slower, but if they are on a sign cusp you still have to check.

Consideration needs to be given to any sign cusp planet. Look out for retrograde motion as well.

You may need to keep an open mind about which of the potential two signs a cusp planet could tenant until you fully understand the chart.

Exception 2: The Moon

The second exception is the Moon.

The Moon trots along at give or take 13 degrees each day.

Therefore, in one 24-hour period the Moon will travel about 13 degrees through the zodiac.

So, for a 12-hour period, and here I mean our noon chart, it can potentially.

move around 6.5 degrees from the noon position.

That is, the Moon can travel up to 6.5 degrees before noon and 6.5 degrees after noon.

This means that if the Moon in the noon chart is 6.5 degrees from either sign boundary, the before sign and the after sign, it will be in that sign.

And for more certainty, if the Moon at noon is placed between 6.5 to 23.5 of a sign, it will be in that sign.

Double Check

Note, if the Moon is bang on 6.5 from a sign boundary, you must go back and check the lunar daily motion on that particular day. If it is greater than 13 degrees you will have to rethink the sign.

In a noon chart for example:

  • If the Moon is at 6 degrees Virgo it could be in the previous sign of Leo.
  • If the Moon is at 10 degrees Sagittarius it will definitely be in the sign of the Archer.
  • If the Moon is at 26 degrees Pisces it could be in the next sign, Aries.

You can tinker with an unknown birth time for days.

A Better Solution

But what if there was an easier way to find the birth time if you don’t know it?

Fortunately for us there is.

It’s called rectification.


Rectification is a highly skilled astrological technique which explores the options for a better birth time and therefore firms up the Ascendant and the house cusps.

Not every astrologer practices rectification.

Rectification is usually used in two specific instances:

When there is no birth time, like what I’m talking about here with the noon chart, and,

If there is a birth time, but the chart doesn’t seem to fit comfortably with the person.

As maths is not my strong suit and due to the heavy load of numbers, maths and statistics required to work out someone’s rectification, it’s not something I do.

I will admit I have done rectification back in the day, but now I don’t do rectification nor do I enjoy doing it.

I feel it’s better left to the specialist astrologers who relish maths and love practicing rectification to help others.

Rectification Specialist

This week I am thrilled to share with you the conversation I had recently with professional astrologer, and rectification specialist, Norma Lachance.

Norma is a highly skilled professional astrologer with an advanced certificate (soon to be a diploma) from the Faculty of Astrological Studies, London, England.

And if you don’t know, the Faculty diploma is the world class honour you can receive in astrology today.

I’ve known Norma for about seven years.

She is the only rectification specialist to whom I confidently refer my own clients when they want, or need, their birth chart rectified.



I love Norma’s style of astrology and the high energy and sparkle which she brings to her work.

That is why I’m supremely confident in referring her to you.

And let’s be quite clear here.

I want you to know that I’ll only recommend talented people to you, whom I believe will bring value and goodness into your life.

It’s important that you can trust the good-hearted people in the astrology community whom I send your way and those I feel are worthy of your time.

Listen to our rectification podcast episode and if you think it is something that will be right for you, reach out to Norma and let her know that you discovered her from me.

Extend Yourself

You can extend yourself and lean into rectification in a couple of ways.

See if you can find someone in your family, friend circle or general client base who has an Ascendant within one degree of a sign cusp.

So, their Ascendant will either be at 0 and some minutes or at 29 degrees and some minutes of any sign.

Then in your astrology journal please do the following:

  • Look at the current Ascendant degrees and minutes and step the chart forward or backward to see how many minutes in time it would take to change the rising sign. Write this time down. It probably will be under ten minutes.
  • Note exactly how many minutes (of arc this time) is equal to the time in minutes. This will probably be less than 59’. You could also ask, “How far is the Ascendant from the cusp?” Which will return the same answer.
  • Consider whether the new rising sign would be a better fit for the person and their personality. Avoid making a snap decision here. Give this some thought. As I like to say, let it percolate.
  • Decide if the new chart ruler, the planet that rules the new Ascendent, better reflects the type of person the chart is for. This is sometimes clearer with some pairs of planets whose energy is quite different.

Example 1: Sun and Moon cusp – Cancer/Leo.

Example 2: Venus and Mars cusps – Aries/Taurus and Libra/Scorpio.

Example 3: Jupiter and Saturn cusps – Sagittarius/Capricorn and Aquarius/Pisces.

Extend Yourself Further

Think about whether you are ready, at your stage of astrology knowledge, to learn chart rectification.

Remember, rectification is not for everyone.

If you think rectification is something that interests you here are 3 ways to start exploring it now:

  • Read this book The Complete Book of Chart Rectification by Carol Tebbs from Llewellyn Publications.
  • Get your chart professionally rectified by Norma.
  • Invest in a serious rectification course with Norma. Learn how to rectify charts for your family, friends and clients.

I’d love to hear how you get on. Let me know your answers by completing this quick one minute survey.

I’ll report back on the results in a later email.


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Author Bio

Alison Price: Professional Astrologer

Alison helps you uncover your individual creativity and lead a fulfilling life using your own astrology. She shares her wisdom from the heart with a touch of humor. She offers Consultations for everyone and Coaching for Aspiring Astrologers.

If you’d like to get in touch with Alison, you can reach out to her via email at

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