Planets and points in a Horoscope are considered “in Aspect” to each other when they are in specific angular distance, measured by the shorter of the two arcs. Certain angular distances create effective vibrations that resonate to the chart native. Aspects are usually measured in the ecliptic, regardless of latitude. Planets are rarely in exact aspect in absolute terms, because that would require them to lie on a common plane.

Harmonics are waves of one sort or another. Humans are sensitive to wave signals, of various types and intensities. Planets give the appearance of generating harmonic, gravitational vibrations from their positions in the Zodiac, which is why we even bother with Astrology. Harmonics explain why some aspect angles between the Planets and Earth are more palpable to us.


The strongest harmonics produce the strongest effective angles, and therefore have more influence on us. These harmonics, and their aspects, are based on divisions of the 360 ˚ Zodiac.

Finding the mid-point of the bodies in aspect is also important to their inference. The mid-point is calculated by taking the average longitude of the planets. This results in two mid-points in our 360 ˚ Zodiac – a near point and a far point. Both points are important, though the near point is often considered stronger. The location of the mid-point shows us where the energies of an angular aspect operate, and better help us understand their energies and how to best express them.

“Orb” is the degree of variance from an aspect being exact. Different astrologers consider aspects using a variety of orbs. My experience tells me that the tighter the orb, the stronger the influence. However, even variance of 3-4 ˚ or more doesn’t disqualify an aspect from interpretation. It simply means the effect is a bit less intense.

“Applying” means the faster of the two bodies is moving toward the exact aspect. “Separating” means the opposite. “Dexter” is an older term used to describe bodies moving toward a conjunction, and “Sinister” describes bodies moving toward an opposition.


Major aspects are the primary angular relationships astrologers look for in charts. For mathematical reasons, their harmonics produce stronger vibrations in the angles than do Minor aspects, discussed later.

0 ˚ (360 ˚) is the fundamental, First Harmonic. Two (or more) Planets or points are said to be in Conjunction when they’re in the same degree of a Sign. The influential vibrations of the bodies in conjunction are blended together. While most astrologers recognize the conjunction as a “positive” aspect, it can most certainly be difficult. For example, suppose we’re looking at a conjunction of Mars and Jupiter in a chart. We could quickly analyze it as “expansive activity”, “excessive anger”, or even, “big headache”. Hence, the energies of a conjunction need to be interpreted more completely. We have to consider the location of the conjunction by House and Sign, as well as the conjunction’s relationship to other planets and points in the chart. Obviously, the mid-point doesn’t apply to a conjunctive aspect.

180 ˚ is the Second Harmonic. Bodies are considered to be in Opposition when they lie 180 ˚ apart from each other. In the opposition, the influential energies of the planets/points in question are irreconcilable. They are simply pulling the chart native in two opposing directions. The influence can produce a state of vacillating inertia, or a fierce conflict, whether internal or external. Again, the nature of the opposition needs to be integrated with the whole chart. A good deal of the native’s life may be spent trying to find a reconciliation; this is more likely in youth, because in old age, the native has probably resigned himself to the natural tension.

The opposition produces two, generally equidistant mid-points, which show us where and how this frustrating energy is often expressed.

120 ˚ is the Third Harmonic. Bodies are said to be in Trine when they’re located 120 ˚ apart. The energy of the trine is traditionally considered to be easy, flowing energy. The principles of the planets/points involved cooperate. Sometimes trines represent special skills a person naturally possesses, which can be either beneficial or difficult. For example, trines involving Neptune, in my experience, often involve addictions to drugs or alcohol, because intoxication is a natural state for that native. On the other hand, a trine involving Venus and Neptune could be “ideal beauty”, or “poetic music”. A trine between Saturn and Uranus could show a person who easily limits themselves to online activity, to give another example.

90 ˚ is the Fourth Harmonic. Planets and points are in Square when they fall 90 ˚ apart from each other. Squares represent tension, but unlike the opposition, there is a better possibility of integration of the discordant energies. This is because the near mid-point of the bodies in conflict shows us where to find a common ground for their energies. A square between the Sun and Moon often appears in the charts of those who feel they’re never quite being true to themselves, as the inner Moon and outer Sun don’t jive well. But the near mid-point shows us where that native can find “relief” from that discordance.

60 ˚ is the Sixth Harmonic. Bodies are in Sextile when they’re 60 ˚ apart from each other. The sextile is generally considered a flowing aspect, because it is related to the Trine. It has been traditionally associated with opportunities; whether those opportunities seem obvious or not, or whether they’re taken, is often the job of the astrologer. Natives with sextiles in the chart often feel like they might be missing something. Others feel like they end up doing the same things over and over, because that’s what always happens. A Moon-Venus sextile might be very easy and pleasant to use, perhaps, for a musician. On the other hand, a Mercury-Neptune sextile could provide opportunities for nebulous communication – a pathological liar, for example.

Minor aspects are also calculated by Harmonics. I consider Minor Aspects to be rather important, however, because they represent subtler nuances. Using mid-points with Minor aspects has often led me to find deeper, more intriguing relationships between bodies in a chart and the Major Aspects.

semisextileSemi-sextile, 30 ˚, 12th Harmonic: Energies are similar and not, simultaneously.

quincunxQuincunx, 150 ˚ is not quite an opposition; the energies involved can’t quite “see” each other, and try as they might to gel, it’s always a miss.

quintileQuintile, 72 ˚, 5th Harmonic: These often signify openly expressed talents. Semi-Quintile, 36 ˚, 10th Harmonic, however, is indicative of interpersonal difficulties.

biquintileThe Bi-Quintile, 144 ˚, also represents talent and skill.

semisquareSemi-square, 45 ˚, 8th Harmonic: These function very much like Squares, in that they invoke tension. Sesquiquadrate, 135 ˚, is similar.

Novile, 40 ˚, 9th Harmonic: These tend to represent what the native can, or does, achieve. In some interpretations, they represent the nature of the marriage partner. The Ninth Harmonic is called Navamsa in Hindu Astrology.

Other Minor Aspects can be calculated based on divisions of 360 ˚… No doubt, then, there are plenty of Harmonics to work with – and they’ll eventually find their ways into the practice.

The Natal Planets in Aspect               The Composite Planets in Aspect