The ancient Babylonians and the Hellenistic astrologers used twelfth-parts (dwads or dodecatemoria) of the signs of the zodiac. The idea is that each sign can be projected onto the entire zodiac circle, with each 2.5 degrees (twelfth-part) of a sign being projected onto an entire sign of the horoscope wheel.
In the system of Manilius, the first 2.5 degrees of a sign is projected onto the sign itself, the 2nd 2.5 degrees onto the following sign, etc. Thus, for example, the first 2.5 degrees of Virgo would project onto all of Virgo, the second 2.5 degrees of Virgo onto the next sign Libra, the third 2.5 degrees of Virgo onto the next sign Scorpio, and so on around the wheel.
Paulus of Alexandria (4th century CE) thought it was more reasonable to begin the projection from the point in the zodiac at which planet you were studying was located. For example, using Virgo again, suppose Mars occupied 4 degrees of Virgo, which happens to be part of the second 2.5 degree segment of Virgo. In this case the first 2.5 degrees of Virgo would be projected to the previous sign, Leo. The segment containing Mars (the second 2.5 degrees of Virgo) would be projected onto Virgo itself, the third 2.5 degrees of Virgo would be projected onto the next sign Libra, and so on around the wheel.
From what I have seen in the literature, most astrologers tend to use the system of Manilius.
Now to the use of twelfth-parts in horary. Masha’allah in writing about “hidden things” noted that the twelfth-part of the Ascendant of a horary chart would reveal the querent’s concerns and intentions in consulting the astrologer. He gave an example of the Ascendant in the 12th degree of Aries, which lies in the fifth 2.5 segment of Aries. Hence the 5th Whole Sign house from Aries, which is Leo, reveals the querent’s concern or intention. In his example there were no planets in Leo, so he looked to the ruler of Leo, the Sun, which happened to fall in Libra in the 7th Whole Sign house from Aries. Masha’allah concluded that the querent wanted to know about a child (5th house) who was seeking the querent’s wife (7th house). Had a planet been located in Leo, Masha’allah would have incorporated the meaning of that planet into his interpretation.
To test this theory, I looked for a published horary that was difficult to interpret to see if the twelfth-part would add additional information. I found such a chart on the site of astrologer Christopher Magnus. The gist of the question was that Christopher had misplaced his keys and was unable to find them despite a very careful week-long search of his house. He finally decided to cast a horary chart at 10:17 AM EDT, on 18 August 2012, a Saturn day during a Sun hour, at coordinates 40N35, 73W40.
After analyzing the chart, Christopher was able to find the keys. He had last seen them two weeks earlier, when he went with his partner to a confirmation service at a church in a seaside resort two hours from his home. He brought a change of clothes to wear after the formal church service, but he was not feeling well because of recent surgery, so he and his partner decided to go home. Because of the pain from surgery, he took some pain medication which probably affected his memory of the event. As a result, he assumed the keys were in one the pockets of his informal clothing, which he mis-remembered wearing, and instead found them in the pocket of his more formal black suit which was in an upstairs closet.
Here is Christopher’s horary chart with the dodecatemoria (Maniulius method) around the outside of the wheel.
(Chart and table below are cast using the program AstroSpica by Elías D. Molins.)
Christopher is the querent, signified by the Ascendant at 14 Libra 14, ruled by Venus. The missing keys are a 2nd house possession, signified by Mars because Scorpio is on the cusp.
Mars in Libra in the 1st house suggests that the keys are in his home and that he will find them. Libra, an air sign, could indicate a location in an upstairs room. The first house has to do with one’s appearance and Libra is associated with fashion and looking good, so the location of the keys in the pocket of his formal suit makes sense.
The twelfth-part of Venus, the Ascendant ruler, lies in Scorpio, indicating a mutual reception between Mars in Libra and the dodecatemorion of Venus in Scorpio. This is yet another testimony that he will find the keys.
The 12th part of Mars (the keys) lies in Leo on the Regiomontanus cusp of the 12th house of confinement due to illness. His recent surgery was the reason the took pain medication, which made it hard to remember where he put the keys. The dodecatemorion of Mars is disposed by the hour lord Sun, whose own 12th part is conjunct Jupiter in the 9th of long trips and church services. (Mars also rules the 7th house of his partner who played an inadvertent role in the misplacement of the keys.)
Now let’s look at the 12th part of the Ascendant and apply the reasoning of Masha’allah. As the table below indicates, the 12th part of 14 Libra 14 lies at 20 Pisces 50 (the sixth Whole Sign from the Ascendant), which happens to lie on the 6th house Regiomontanus cusp of illness in the decan and terms of Mars (the keys). Somehow an illness or an ill person (he recently had surgery) is connected with the missing keys. In addition, Neptune in Pisces in the 6th Whole Sign from Libra indicates that a drug played a role (he took a pain killer which affected his memory of where he left the keys). The traditional ruler of Pisces is Jupiter, which lies in the 9th house of long trips and church services, which is where he last saw the keys.
In summary, the 12th parts do seem do add another dimension to horary analysis. In this case, they point to an ill person (6th house) taking medication which affected his cognition to the extent that he could not remember (Neptune in 6th) where he put the keys on a trip to a church service in a distant location (9th house). It appears that Masha’allah knew what he was doing.
An incidental but interesting feature of this chart is that Valen’s “Lot of Accusation” (sometimes called the Lot of Infortune and indicated in this chart by the red cross on the ASC) at 15 Libra 58 lies on the Ascendant and receives a square from the Asc-ruler Venus in Cancer, suggesting that Christopher will have trouble finding the lost object, and perhaps that its being misplaced is related to being away from home. According to Curtis Manwaring:
“Lot of Accusation:
- [Day] Lot = Ascendant + Mars – Saturn
- [Night] Lot = Ascendant + Saturn – Mars
According to Valens this lot indicates the house [sign] through which the native is likely to experience failure, dangers, or downfalls. This lot is also known as the lot of injury and sometimes the lot of being away from home.” (italics mine)
The twelfth-part of of the Lot of Infortune/Accusation happens to lie in the 7th Whole Sign from the Ascendant, representing his partner who was inadvertently involved in the misplacement of the keys (Mars) while the two of them were away from home. The dodecatemorion of this Lot near Uranus suggests that an unexpected change of plans involving his partner may also have been a factor.