Limits of Computer-Generated Natal Charts

astrology reading, Magus, Services at Conjure Work,

There are lots of free sites online that allow you to plug in your birth information and get a quick report on your natal chart (birth chart). For the most part, this is great. Most people find them to be pretty useful. They do have limits though and that’s what I’m going to discuss here.

When you plug your birth information into a computer program or website to get your natal chart and the interpretation of it, a couple of things need to be strongly considered.

Zodiacal Rulerships, Conjure Work, astrology readings, natal birth charts
Zodiacal Rulerships

Vital Statistics

First, it’s vital to know the Rising Sign for a complete, accurate analysis. The Rising (also known as the Ascendant or AC or ASC) is how we determine the astrological Houses for that individual. For example, having Mars in the 1st House is very different from having Mars in the 3rd. Having Saturn exactly conjunct to one’s AC is a very different experience than that of having Saturn in one’s 12th House.

If we don’t know the correct time of birth, then we cannot say with any real certainty which Signs fall in which Houses for the native (the person who the chart is describing). The Ascendant or Rising Sign is the zodiacal Sign (like Pisces, for example) that was popping up, just over the Eastern Horizon, at the moment of birth. It tells a great deal about a person… a great deal.

The correct time of birth is usually listed on a person’s long form birth certificate (not the same thing as the short form). This can be obtained from the Bureau of Vital Statistics for the State and/or County of the person’s birth. Usually, a quick Google search will yield a website and an online form where you can order it and it usually costs something like $10-25. Just be sure to specify that you want the long form birth certificate.

Artificial Intelligence

Second, there are only so many profound observations that a computer can make about an individual. This is because the computer is simply noting where the planets are at the specified place, date and (hopefully) the exact time of birth.

Then, it spits out pre-written explanations for various factors that pop up in all charts. It is however, limited to looking at one factor of a chart at a time.

For example, the program is stocked with descriptions for Jupiter. There will be a standard write-up for Jupiter in each of the 12 astrological Signs and a description of Jupiter in each the 12 Houses. What is essential to note is that these will be separate descriptions.

Stockpiles of Information

If you have 12 Signs and 7, classical Planets (Sun, Moon, Mercury, Venus, Mars, Jupiter, Saturn) and 3 Transcendentals (Neptune, Uranus and Pluto), then that’s already 10 Planets times 12 Signs, meaning 120, separate descriptions of Planets, as they tend to manifest in the various Signs.

If you also have 12 descriptions of each Planet, as they tend to manifest in each House, then you have an additional 120 descriptions, right there.

If we attempt to write an additional description for each Planet, in each possible Sign… and… in each possible House, we are getting into exponents and a project that would last many years, if not decades. Most businesses that create software for astrology just don’t have that kind of time or resources of time and labor.

Implications of Exponentials

So, we might have in our natal chart, say… Jupiter in Gemini. Additionally, Jupiter might be in the 12th House (which you can only say for certain IF you know the correct birth time).

The computer-generated chart will do a fairly good job of summing (as best as can be done in a short blurb) how Jupiter tends to act, when in Gemini. It will do a pretty decent job of describing Jupiter in the 12th House, as well.

However, it becomes increasingly difficult to Jupiter in Gemini, IN the 12th House. If we then try to add in other factors, it gets beyond the scope of a computer, rather quickly.


Consider of few of the following, potential factors:

Jupiter retrograde (or stationing retrograde or stationing direct)

Jupiter is in the 2nd decan of Gemini, not the 1st or the 3rd decan

Jupiter below the horizon (as opposed to above it)

Jupiter conjunct Mercury and squared to the Moon

Jupiter within its own Bounds (a narrow space of Gemini, roughly 6-7 degrees, in which Jupiter is said to be stronger and more able to do what Jupiter does well)

Scratch the Diamond Jewel

Realize that we’re just beginning to scratch the surface of describing all the intricate forces that act on an individual’s character and the experiences that they typically run into. The lists of possible factors in a chart can be analyzed for not just hours but days and weeks and months on end.

It’s difficult, if not impossible, to describe via a computer program, what that same Jupiter placement will be like, if for example, almost every other planet in the person’s chart is in a Fire Sign. That would indeed be a Jupiter that behaves differently than if the other Planets were balanced throughout the other Elements of the chart. Having only Jupiter in an Air Sign (Gemini, in this case) and having 5 Planets in Water Signs and the rest in Earth would be decidedly unlike having 2 or 3 Planets in each Element.

The Decans and their Ruling Planets

Job Security

Only a human can sort all those things out. Unless someone spends decades writing out all the possible permutations. Even still, they’d never finish.

Of course, the most relevant, beginner-level points of interest can easily be plotted out by simply looking at each Planet, in each Sign and how they aspect one another.

Therefore, the computer charts are excellent starting places and make good reference materials for anyone seeking to better understand themselves. It’s highly advised that you have a computer-generated report for yourself, if for no other reason than the fact that it will spur your thoughts and generate questions that you can write down and ask a professional astrologer to go into more detail about.

Gratuitous Self-Promotion

Naturally, when you have an astrological reading with me, I will provide you a copy of your natal chart and a computer-generated chart for your natal descriptions. These reports are generally about 18-22 pages in length, a lot more than what most automated websites give you.

Then, we’ll spend the time of your session going over all the details, the ins and outs of each of your Planets, the Signs and Houses they fall in, the aspects they make to each other and all the other relevant details that you will obviously want to know about the weird, cosmic schematic or blueprint that is your own, personal, natal chart.

2 thoughts on “Limits of Computer-Generated Natal Charts

  1. Harshita says:

    Hi, i read your note and found interesting. I have a very fundamental question. I have put my details on various computer generated charts available and found that i have got two different results from these. some considers my details under Cancer moon, aries rising, leo north node and others leo moon and taurus rising, virgo north node. I also have a handwritten birth chart which says Cancer moon. I would like to understand why softwares vary. One thing i have noticed is that sofware stating it as vedic charts put me under first option – cancer moon and other charts put me under second option, leo moon. Now what is accurate? pl help me understand. thank you!

    • Magus says:

      Hi. You’re dealing with a difference of calculating the Houses. First, make certain that the date, place of birth and time of birth are exactly correct in each situation; any errors in input of the data will result in dramatic differences and will be very confusing.

      Next, decide on which House system you want to use and plug that into the program. The Vedic system is ancient, from India. They have an entirely different mythology and way of working than what we have here in the West. Unless you intend to learn Vedic astrology, I would not recommend using the system’s way of House calculation.

      But even within Western astrology, there are some different methods. The most widely used, modern system is Placidus. However, I highly recommend the medieval method of Whole Sign Houses. It’s not only spot on accurate but it’s an easier method to understand and it’s more traditional.

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