Now, where did the 5° "rule" come from? Deborah Houlding states:
[According to Ptolemy] the twelfth part of the zodiac surrounding the horoscope, from 5° above the actual horizon up to the 25° that remains, which is rising in succession to the horizon. The 5° misplacement from the ascendant has caused much debate; the most sensible explanation being that the virtue of each house has been assigned a 5° influence before the cusp. The same approach is used today by astrologers schooled in traditional techniques, so that if a planet is within 5° of the next house cusp, it is considered to have its influence within the context of that house.
Interestingly, according to Stephen Arroyo, in a chapter titled "A Crucial Point for Interpreting Houses", "One should note that planets that are conjunct a house cusp within 6°, on either side of the cusp, should be regarded as strongly in that particular house." Arroyo goes on to illustrate the concept with a planet 6° before the 5th house cusp and stating that the planet conjuncts the 5th cusp.
To add even more excitement to the 5° or 6° rule, Robert Hand states in his Horoscope Symbols,
I now follow the ancient Greek idea that a cusp is the peak of a house's energy, though not the beginning of the house. The peak seems to be 3° to 7° after the beginning. Determining the actual beginning of the house is not important, however, because it is also apparent to me that the transition is not sudden, but gradual. Thus my Sun, which is about 4° back from the 6th house cusp, is in the border area and is a mixture of 5th and 6th.
My current viewpoint is that:
- Imagine there are 12 detached houses that are lined up in a circle. Each house is owned by a house owner. Between two houses is a common plot of land that is jointly owned by two owners. When a person is standing on that plot of land, he is in the domain of both owners.
- Returning to our example above, Jupiter is in 4° Libra and the 5th house commences at 8° Libra. My view is that Jupiter is in the "ending phase" of the 4th house and the "starting phase" of the 5th house. In essence, Jupiter is therefore in the 4th but conjuncts the 5th.