Finding Twelfth-Parts in your head or with Morinus

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What are Twelfth-Parts?

Many of the articles on this site feature the use of twelfth-parts. Those unfamiliar with the twelfth-parts should check out the information I’ve provided on them starting with the introductory article on them.  In this article, we look at finding twelfth-part positions in your head and with free software.

If you would like to use free software to find twelfth-parts then please download the Traditional Morinus software program (click to go to download page). It has undergone a number of great updates, including the addition of twelfth-part calculation. Please see the article on the installation of Morinus.

Finding Twelfth-Parts in Your Head

Of course, you can calculate twelfth-parts with pen and paper.  It’s simple and was discussed in the introductory article on the twelfth-parts. However, I’d like to highlight some quick and dirty techniques for finding twelfth-part sign positions. Below are my tips. The numbers that I give are where the twelfth-part sign starts, so always think in 2.5 degree segments. Remember that 10 goes from 10°00′ to 12°30′ of that sign.

0 = Same Sign

This is the easiest one to remember.  If the planet is in the first 2.5 degrees of any sign, from 0°00′ to 2°30′, then its twelfth-part is in the same sign.

10, 20 = Trine, Same Element/Triplicity

If the position is in the 2.5 degrees following degree 10 or 20 in the sign then it is in the same element. It is in one of the signs trine to that one. 10 is the beginning of the first trine, the one following. 20 is the beginning of the second trine, the one prior.  For instance, if the Moon were at 10°30′ Scorpio, then the twelfth-part Moon is in Pisces, the water sign after Scorpio.  If it had been at 22°00′ Scorpio, then the twelfth-part Moon would’ve been in Cancer, the water sign before Scorpio.

15 = Opposite Sign

If a planet were at 15° (up to 17°30′) of some sign, its twelfth-part would be in the opposite sign.  For instance, you see someone has Jupiter at 16°47′ Cancer. Capricorn is opposite Cancer, so you know that the twelfth-part of Jupiter is in Capricorn.

5°, 25° = Sextile

You see Jupiter at 6°33′ Libra in someone’s chart, but where is it’s twelfth-part?  The segment beginning with 5° is the sign that is the sextile after the one occupied. The segment beginning with 25° is the sign that is the sextile before the one occupied.  5 and 25 – easy enough to remember, especially since 25 is 5 squared, and the sextile is of the nature of Venus who makes a five-pointed pentagram figure in her course.  Returning to our example, the twelfth-part of Jupiter must be in the following sextile, Sagittarius.

30′ = 6 degrees of a sign for twelfth-part

Let’s return to our example with Jupiter.  Jupiter is at 6°33′, and we determined its twelfth-part is in Sagittarius.  However, where in Sagittarius? We know that Sagittarius starts at 5° Libra and goes until 7°30′ Libra.  Every half degree after 5° is another 6 degrees of Sagittarius, starting from 0°.  Jupiter is about 1.5 degrees past 5°, which is 3 time half a degree.  Each half a degree is 6 degrees, so 3 times 6 puts Jupiter at about 18 Sagittarius.

For fine-tuning, note that every 5′ of a degree equals 1 degree for twelfth-part positions.


In order to get you thinking in twelfth-parts and getting acquainted with these rules, let’s work on a few examples.

Kurt Cobain

Kurt Cobain's Natal Chart
Kurt Cobain’s Natal Chart

Where is the twelth-part of Kurt Cobain’s Venus, planet of love, artistry, and beauty?  Venus is at about 26.5 degrees Pisces.  25 is the magic number here as it is in that 2.5 degree segment after 25.  In the rules above I specify that 25 is the preceding sextile. Venus is in the 7th, Pisces, so the twelfth-part is two signs back in the 5th, Capricorn.  How many degrees after 25 is 26.5?  1.5 degrees.  Each half degree is equivalent to 6 twelfth-part degrees, so the twelfth-part of Venus is 3*6=18 degrees into Capricorn.  18° Capricorn as the position means that Venus is in her own bound and in her Joy (the 5th place of children, creativity, entertainment, and performance is called the Joy of Venus).

Bill Gates

Bill Gates' Natal Chart
Bill Gates’ Natal Chart

Where is the twelfth-part of Bill Gates’ Mercury, planet of commerce, scholarship, and technology?  Mercury is a little more than 16.5 degrees into Libra at 16°36′ Libra.  As Mercury is in the 2.5 degree segment after 15, it is 15 that is the magic number here.  15, being half of 30, also puts us halfway around the zodiac from Libra to the sign that is its opposite Aries.  What degree of Aries is Mercury’s twelfth-part?  Mercury is a little more than 1.5 degrees past 15, and 1.5 is equivalent to three 1/2 degree segment.  Again, each 1/2 degree segment equates to 6 degrees, which puts us 18 degrees into Aries.  There is an extra 6′ though, and every 5′ is another degree, so it must be at 19° Aries.  Therefore, the twelfth-part of Bill Gates’ Mercury is in its own bound in Aries, with the sect light, the Moon, in the 10th house of authority, honors, and profession.

Whitney Houston

Whitney Houston's Natal Chart
Whitney Houston’s Natal Chart

Where is the twelfth-part of Whitney Houston’s Venus?  The magic number is 10, as it’s in the 2.5 degree segment after 10° Leo.  As mentioned in the rules above, 10 puts is in the next sign of the same element. The next fire sign or first trine is Sagittarius, the 10th house. What degree in Sagittarius?  Venus is at 11°12′ Leo, so it is two 1/2 degree segments plus 12′. Each half degree segment gives 6 degrees, bringing us to 12.  Then every 5′ segment is a degree, and there are two of them in 12′.  This brings us to 14° Sagittarius. Houston’s Venus twelfth-part is in its own bound in the 10th house of authority, honors, and profession.

Dalai Lama

Dalai Lama's Natal Chart
Dalai Lama’s Natal Chart

Where is the twelfth-part of the Dalai Lama’s Jupiter?  The Dalai Lama’s Jupiter is in the 2.5 degree segment after 12.5, so it doesn’t fit exactly with any of our rules.  However, our rules can lead us right there.  12.5 is one segment after 10, and one before 15, so Jupiter is one sign after the first trine and one sign before the opposition.  We can go either way.  If thinking in terms of “10, plus one sign”, then we would find Pisces, which is the next water sign after Scorpio, and we would put Jupiter in the next sign, Aries.  In terms of “15, minus one sign”, then we would find Taurus, the sign opposite Scorpio, and put Jupiter in the one before it, Aries.  In any case the twelfth-part is in Aries.  But what degree of Aries?  Jupiter is at 13°28′ Scorpio, so it is nearly 1° past 12°30′ Scorpio.  Each 30′ equates to 6°, so it is nearly 12° into Aries.  5′ is equivalent to a degree and it is only short by 2′, so it is less than 12°00′ Aries, but by less than a full degree.  This puts the twelfth-part of Jupiter at 11° Aries.  The twelfth-part of the Dalai Lama’s Jupiter is in the Venus bound in the 10th house of authority, honors, and profession.

Finding Twelfth-Parts in Morinus

Recently, the developers of the free, open-source, astrology program, Traditional Morinus, added twelfth-part capability to the program. Please read the article on basic installation and chart entry in Morinus.


Once you have Traditional Morinus installed and ready to go, load one of your charts, or the chart that it comes with. Let’s look at its default chart, that of Morinus (Jean-Baptiste Morin), the prolific 17th century French astrologer and mathematician.  Then go to the Option menu and Appearance I, or hit SHIFT-A (that is, hold Shift and press A). Click the bullet in front of “Dodecatemoria” to turn on the twelfth-parts, which will appear marked along the outer edge of the wheel.

I also recommend adding the terms (bounds) into the wheel, making the wheel black and white, and thickening up the lines for the angles, as shown below.


A couple other things you can do quickly to set your charts like mine include pressing SHIFT+F6 to switch to whole sign houses, and pressing SHIFT+W to have the Node position be the true position (note: I may have still had the Node at mean position in some examples).  Finally, make sure you press SHIFT+U, so that your settings will be saved for the next time you start up the program.

Morinus Twelfth-Parts

Morinus' Natal Chart with Twelfth-Parts
Morinus’ Natal Chart with Twelfth-Parts

Look at Morinus! The twelfth-part of Jupiter is right on the Ascendant.  The twelfth-part of Mercury is in its own bound in his 10th.

The Example Charts

Below are the charts that I discussed above, but this time with the twelfth-part placements included.


Cobain with Twelfth-Parts
Cobain with Twelfth-Parts
Gates with Twelfth-Parts
Gates with Twelfth-Parts
Houston with Twelfth-Parts
Houston with Twelfth-Parts
Dalai Lama with Twelfth-Parts
Dalai Lama with Twelfth-Parts

Have fun and feel free to discuss in the comments!

Featured Image Attribution

Frescoes in the Camera degli Sposi by Andrea Mantegna (1473) (cropped) [Public domain] via Wikimedia Commons.



Blogger interested in all things astrological, especially Hellenistic, medieval, Uranian, and asteroid astrology.

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