When you read a chart, you're looking for energetic patterns. The aspects show how planets relate -- blending, harmonizing, clashing or opposing -- to each other or one of the chart points. The angles these create are measured in degrees.
The chart is 360 degrees. When you're looking at the circle, drawn up as an astrological chart, you'll see lines that connect the planets to each other, and these points. Each planet or significant point (ascendant, descendent, midheaven (MC) and lower midheaven (or IC) has its own fixed location (for that moment), indicated by the degree and minute (of ecliptic longitude). Don't worry about minutes when you're starting out.
The aspects are energetic relationships between planets and points. And, when you're looking at transiting planets, aspects are the angles formed to the planets or points of the chart you're reading. For example, you may have Sun Virgo trine Jupiter Taurus in your chart, and that's an influence you'll live with all your life. Then there's transiting Venus, for example, in trine to your Sun, because it's within orb (close enough to exact) of a 120 degree angle. Trines are often between planets in the same element (120 degrees apart), and squares between planets of the same quality (90 degrees apart).
Tip to Remember: There are no bad aspects, since even the square provokes us to grow into wholeness. Knowing the hot spots of your chart, where planets throw sparks or pull in two directions, gives you valuable awareness as you seek to live out these energies in your chart.Major Aspects
A stand-off between two seemingly polar opposite forces. On the chart, the planets or points are 180 degrees apart (or close in orb to an 180 degree opposition). This inner conflict plays out in relationships, where it's possible to see this oppositional factor, in the drama of life. You might even see how someone (or a series of someones) is embodying a planet for you!
One example, with Mars opposing Saturn, the motivational urge (Mars) is in opposition to the demands of structure or authority (Saturn). With this natal opposition, we might often be at odds, with authority figures, from teachers/parents, to more abstractly, "The Man."The Conjunction
When planets are very close in orb (0 to 10 degrees), they're conjunct. They're combined energy is a force to look at, with attention to which planets (or chart points) are involved.
Some blending combinations magnify the harmonious effects, like the Jupiter-Venus, for example. Other combos have built-in challenges, but still indicate an amplified energy. One would be the Saturn-Mars conjunction, where the Saturnian instinct for being deliberate meets the raw impulsive drives of Mars.
A planet smack dab on the Sun is cazimi, an Arabic term meaning "In the heart of the Sun. A planet close to the Sun is combust, and is vitalized. More than two planets forming a conjunction is a stellium.The Square
The squares in the birth chart are pre-loaded or highly charged relationships. This is an angle of 90 degrees, from exact (the strongest influence) up to 10 degrees in orb.
The square creates tension, from subtle to extreme, depending on which planetary players are involved. Squares to Pluto, for example, are known to be relentless, and yet where your most profound growth happens.
The square has been likened to Saturn, because it must be confronted, and brings up fear. It might feel like an inner conflict that's dangerous, because it creates a loss of control. When two planets are square, they're engagement creates an effect that can take on a life of its own.
Squares are provocative, and can be motivating. A Sun-Saturn square, for example, keeps you from ever resting on your laurels. You're always sensing that Saturnian demand to make the most of the time you have, and grow into your full potential. Like Saturn, squares build character, a sense of perseverance, and hard-won wisdom from experience. It's very trial and error, so be especially patient with the squares you see playing out in the birth chart.The Trine
Trines feel like harmonious gifts in the birth chart. They are at an angle of 120 degrees. They're influences that seem to bring luck or opportunities without much effort. A trine is ease, and this can be taken for granted, where you just go with the flow. All play and having things handed to you on a silver platter is often not truly satisfying in the end. It leads to a sense that you had so much, but didn't appreciate it and build on it.
When you invest in the area represented by the trine, there are big rewards. Sometimes we focus too much on the challenges (squares and oppositions). It's useful to bring attention to the trines and sextiles (a more subtle harmonic), and magnify their effect with right action, creativity, productive effort.The Sextile
The sextile is an angle of 60 degrees between planets, and is considered a beneficial influence, though not quite as strong as the trine. There's support between the planets. It's easy to find a harmonious rhythm there, and so adds a sense of ease.