The magic wedlock of planetary symbols
In mathematics, a point is equidistant (or equally distant) from two other points when it is the same distance away from them. In the astrological scenario, an equidistant point (midpoint) is obtained from the arithmetic mean of the ecliptic longitudes of two planets. The general formula for finding the midpoint is:
Longitude planet 1 + longitude Planet 2/2.
For example, if Mars is at 0° Taurus and Venus at 0° Pisces, we have:
30° (Mars) + 330° (Venus) = 360° / 2 = 180° = 0° Libra.
That is the farthest point from the two planets; the other midpoint, opposite 180 ° to the first, is at 0° Aries.
In the work by Guido Bonatti  Liber Astronomiae, there are indications of the midpoints applied to a natal time correction technique to predict the outcome of the campaigns of the Count of Montefeltro. The noble defeated the enemy but was wounded in the fight, just as foretold. But we find a more systematic use of them in Martin Pegius, a 16th-century Slovenian lawyer and astrologer. In more recent times, Alan Leo  has used the midpoints together with the directions of the solar arc .
With Alfred Witte  and the Hamburg School of Astrology (also known as Uranian Astrology), midpoints were framed in an astrological system renewed on the premises, using a 90° graph instead of the usual 360° of the traditional zodiac. Reinhold Ebertin’s Cosmobiology originated from the same current ; however, Ebertin eliminated the use of trans-Neptunian planets while maintaining the Hamburg School’s theoretical structure and midpoints.
Beyond the specific uses described above, midpoints also find application in traditional interpretative astrology. A midpoint becomes a sensitive place with which the planets – but also the Moon, the Ascendant and Midheaven – can interact, both in the natal configurations and for transiting or progressed planets. In composite or synastry themes, one can still read the aspect between the planet of one subject and the midpoint in the chart of a second subject. The aspects considered significant between planets and midpoints are conjunction, opposition and square; some astrologers take into account the minor aspects of semi-square (45 °) and sesqui-square (135 °).
This is the conventional notation to indicate the conjunction of a planet, in this case, Mercury, with the midpoint of two other planets, Saturn and Pluto.
But the equal sign can designate any aspect with the midpoint.
This is a midpoint tree, which shows us the aspects of the Sun with the chart’s midpoints.
It is easier to use a program that generates both the type of tree shown (the aspects of planets with midpoints) and the list of all midpoints, considering the large number of them in a chart.
The interpretation requires a work of thinning in the choice of midpoints to be privileged for the chart analysis, considering the high number of aspects on the midpoints, and let’s not forget that there are also the traditional aspects. Here are some non-binding but common-sense rules:
- Consider only the midpoint closest to the planets from which it originates and not the opposite point at 180°. Most astrologers rate the far midpoint as much more nuanced in its action than its counterpart. Furthermore, one avoids over-interpretation. Only in one case, when two planets are in exact opposition, they can both be evaluated (because the two midpoints are equidistant).
- Give preference to midpoints formed by planets already in the Ptolemaic aspect.
- Some consider only the conjunction of planets and angles (ASC and MC) at the midpoints, not the other aspects (opposition and square).
- Others limit themselves to assuming only the midpoints formed by the Sun and the Moon to examine the vital potentials and by Venus and Mars for affective matters. In reality, a period of study and practice is needed to understand the midpoints towards which we experience a greater symbolic resonance. It is a very subtle interpretation that requires experimentation and intuition; otherwise, one risks being flooded with unnecessary details.
- Maintain an orb of 1°.
We can express the meaning of midpoints as the filiation of two planets; their symbolism is thus integrated to form the right balance of both factors. It is like the creation from scratch of a zodiacal place that acts as a potential to unfold alternative ways of dealing with existence, a sort of “next level” of experience, as children are for a couple. In this sense, if used with forecasting techniques, it almost assumes a “prophetic” value. It can suggest details to face the setbacks of one’s evolutionary path in a renewed way.
Giving an overview of the meanings of the different midpoints would be limiting; there would be the risk of replicating, at least in part, the symbolism of the planets at stake. It is much better to use an experimental approach by examining the transits of the luminaries over the midpoints of the birth chart. The passages of the Sun can offer an idea of how the joint symbolism of the two planets contributes to manifesting turning points in the House hosting the midpoint. With the transits of the Moon, much faster and therefore difficult to focus on, we can devote ourselves to the analysis of mood swings caused by daily events, a way to direct our emotional reactions profitably. All this does not exclude the attempts of reading with midpoints of other planets.
It is necessary to consider the midpoints as attempts to read an alternative symbolic plane to the traditional one that requires, on the part of the interpreter, a refinement of their intuitive faculties and an original approach to the issues at stake. Cautious integration of some midpoints with traditional tools can be tried or tested, but massive syncretism would only confuse.
 Guido Bonatti (? – 1296-1300) was a famous Italian mathematician, astronomer and astrologer of the thirteenth century. His best-known work, the Liber Astronomiae, remained a classic text for astrologers for nearly two centuries. Despite his declared preferences for the Holy Roman Empire (Bonatti was Ghibelline fighting with the Guelphs of the Papacy), it is said that towards the end of his life, he took the Franciscan Orders.
 Alan Leo, born William Frederick Allan (1860 – 1917), was a London astrologer and theosophist considered one of the fathers of modern astrology. A supporter of psychological analysis-oriented astrology, he attempted to incorporate parts of Indian astrology into the Western astrological model following a study stay in India. Despite his attempts to favour the analytical aspect of astrology rather than the event-oriented model, in 1917, he was convicted of fortune-telling shortly before his death.
 Solar arc-based directions are defined as the difference between the position of the progressed Sun and the natal Sun on a specific day. This arc is added to a planet or a point in the natal horoscope. If the planet directed by the solar arc forms a major aspect with a planet or birth point, an event may occur at the age indicated by the solar arc.
 Alfred Witte (1848 – 1941) was a German astrologer who founded the Hamburg School of Astrology. A great proponent of midpoints in analysis and prediction, he sought a scientific approach to astrology, eventually hypothesising the existence of several trans-Neptunian planets, thus attracting much criticism. Witte’s school has been described, especially in the English-speaking world, as Uranian Astrology.
 Reinhold Ebertin (1901-1988) was a German teacher and astrologer who continued Witte’s studies on midpoints. His School of Cosmobiology proposes a broad application of astrology to medicine and psychological correlations and, in general, an approach based on scientific foundations.