Cosmobiology, an astrological tool for astrologers – a brief learning


Reinhold Ebertin (1901-1988) becomes “father of Cosmobiology”.

1901- Ebertin was born on 16.2.1901; 4:40am MET; Goerlitz, Germany.

1918 -Age 17 introduced to Astrology by his mother Elsbeth Ebertin.

1928-1939 – Active in study, research, practice, published, forming groups and associations.

1940 –Combination Of Stellar Influences (COSI) published

1960’s – COSI translated into English

1970 he and Baldur (his son) presented lectures on cosmobiology at Oxford, Boston, New York and at the AFA Convention in Miami.

Ebertin’s Approach

Revolutionised astrology discarding some time-honoured techniques of traditional astrology. (House system).

Concentrated on planetary and angular relationships.

Focussed on the midpoint interpretations, emphasising  spiritual, psychological and biological factors.

Incorporated the known planets, the Nodes, Ascendant & Midheaven.

Drew upon the cumulative experience of his own research and that of contributors to his monthly journal, “Mensch im All” .

To write “The Combination of Stellar Influences“(COSI), first published, in 1940 from indexed card form.

Considered to be one of the most important astrological texts ever written, and is the “bible” of cosmobiologists and other astrologers who use midpoints.

Let’s start with the 360 ⁰ DIAL of the zodiac.

All of the zodiac signs are represented on the 360 ⁰ dial starting at 0 ⁰ Aries.

Moving in anti-clockwise direction, the 360⁰ dial shows all the signs of the zodiac at 30⁰ intervals. Aries followed by Taurus and so on.

Ebertin chose the 90⁰ dial to show angular relationships. (The 360⁰ dial was divided by 4, or using the 4th harmonic.)

90⁰ chosen as most useful in determining the effects of stellar bodies on individuals

90⁰ Dial brings Quadruplicities together

The first 30° of the dial represent all of the cardinal signs, the next 30°- 60° all of the fixed, and the final 60° – 90° all the mutable signs. 

See above where I have placed the planets on the dial. 5° degree of the fixed is the 35° spot on the dial….



Once you have entered your natal planets according to their degree you will see how conjunctions, squares, oppositions, semi-squares, and sesqui-squares show up on the dial.

Conjunctions, oppositions, squares, will come together showing aspects of action, and events, especially when hit up by transits and progressions.

Semi-squares, (45⁰, sesqui-squares 135 ⁰ appear on opposite sides of dial.) These aspects represent the 8th harmonic of achievement.

Soft aspects, (trines and sextiles were of lesser practical value?) and considered to be indicative of personality and harmony of nature.

The soft aspects will not be so obvious on the dial, so I suggest you always toggle between the house wheel and the dial, to fully ascertain all aspects.


A midpoint is the zodiacally calculated halfway point between two planets or mathematical points (Ascendant, Midheaven, IC, Descendant and Part of Fortune).

Any planet, point or body exactly at this (sensitive) midpoint takes on, and/or is coloured by, the meanings of both planets, points or bodies.

Orbs are 1⁰ – 1.30’

Direct Midpoints

A direct midpoint means that there is actually a planet/point in the natal chart lying in the midpoint of two other stellar bodies.

If we find Venus at 20° Taurus, Sun 20 ° Gemini and Mars at 20° Cancer, we have a DIRECT (occupied) midpoint. (Add distance in degrees of one stellar body A, to second stellar body B, divide by 2 = C Midpoint). A +B ÷ 2=C.

We write this as follows: SU = VE/MA which reads as Sun (SU) is at the midpoint (=) between Venus and Mars (VE/MA).

The meaning of this (direct) midpoint (which ALWAYS contains three planets, points or bodies) is a blend of the meanings of the three factors.

We always use the international two-letter notations of the planets, points or bodies  when writing about midpoint structures.

Example chart of Direct Midpoint

The pointer is sitting on MC=Uranus/Venus.

Example chart of direct midpoint, MC=UR/VE



1.Eyeball the dial/chart

2.Write down in correct style

3.To find more from Solar Fire – Select View chart page.

4. On left select Reports

5. In drop down menu select MidPoint Trees

6.Copy and save.

7.Add some by hand to your natal dial.

Indirect Midpoints

An indirect midpoint occurs when a stellar body makes an aspect, (SEMI-SQUARE, SQUARE, SESQUI-SQUARE) to the midpoint of two other stellar bodies without a physical body at this midpoint.

Direct and Indirect midpoints are given the same value regarding interpretations. (Eleonora Kimmel believed the direct midpoint was stronger.)

Example of an Indirect Midpoint

Neptune is making a square to the Midpoint of Sun/Mars.


The Midpoint between Sun and Mars by calculation is 19⁰37’ Gemini, and Neptune at 18 Pisces is making a square aspect to this point. So NE=SU/MA becomes an indirect midpoint.

Midpoint Axes report in Solar Fire

From Solar Fire –

1. Select View chart page.

2. Select Dial view

3. On left select Reports

4. In drop down menu select MidPoint Axes

The report as shown below will open.

Those midpoints with a “d” are the direct midpoints, those without are the indirect midpoints.

Midpoint Interpretation

Now that you know your midpoints, its time for interpretation.

Many astrology programs will give you an interpretation report. These reports use modernized language in their interpretations, but still remain faithful to Ebertin’s interpretations.

However, using Combination of Stellar Influences (COSI) by Reinhold Ebertin will give you his original interpretations, albeit at times using somewhat harsh language, but one can easily extrapolate the meanings.

Best use for 90⁰ dial and midpoints

As the dial shows up the 4th and 8th harmonic aspects, the conjunction, opposition, square, semi-square and sesqui square, you can quickly ascertain where the “action” will be in your chart.

This is very useful when doing transits, and all progressions, especially using solar arc progressions.

Note: Use the Bi-Dial, to read off the “hits”. You can then use the pointer to find the midpoints. (Most astrology programs have this facility).

Below is a female natal chart on the inner dial with the marriage chart on the outer dial. The midpoint is Jupiter=As/Venus. Indicates “happiness in love” and the Venus to Jupiter hit on the dial, is the “Marriage/Bride” indicator.


Select the important dates in your life, draw up the solar arc chart for those dates, eg Marriage, Birth of child etc., and then place in a bi-dial with your natal chart, use COSI to read interpretations. The results will amaze you!!

Annual Predictions

Using this method, (placing your solar arc chart in a bi-wheel with your natal chart) is a very reliable way to ascertain what is coming up in the year ahead. I use it all the time for my annual prediction chart readings.