Astrology Basics: How to Calculate Planetary Aspects and Angles

Although we all live on Earth, the motions and shifts of many celestial bodies—and their magnetic interactions—subtly influence us. The most obvious influence comes from the Moon because it’s so close. As the Moon rotates and orbits, its changing position interacts with Earth’s magnetic field, giving rise to tides and related ecological effects. In astrology, the positions of the planets are highly valued, since changes in the heavens at any moment are thought to affect what happens next. In fact, many find it quite accurate to infer a person’s character and destiny from the planets’ positions at birth and the angles between them.

When we observe the universe from Earth, it can seem as if the Sun and other celestial bodies revolve around our planet along fixed paths. Although their apparent orbits and distances differ, these paths generally lie on the same plane. In astrology, this circular band is divided into twelve sectors, each named for a zodiac sign. This makes it easy to mark the positions of the planets at someone’s birth on a circular chart using degrees. For example, saying a person has “Venus at 29 degrees Aries” or “the Moon at 28 degrees Libra” specifies exactly where Venus and the Moon were at the time of birth.

Because the twelve zodiac signs represent twelve sectors, each sign serves as a coordinate covering 30 degrees. The order runs Aries, Taurus, Gemini, Cancer, Leo, Virgo, Libra, Scorpio, Sagittarius, Capricorn, Aquarius, and Pisces, then back to Aries. As a result, calculating angles between planets is quite straightforward.

For instance, to find the angular distance between “Venus at 29 degrees Gemini” and “the Moon at 14 degrees Leo,” proceed like this: After Gemini ends at 30 degrees, the next sign is Cancer, followed by Leo. So the angular distance is 30 degrees (Gemini) − 29 degrees (Gemini) + 30 degrees (Cancer) + 14 degrees (Leo) = 45 degrees. Therefore, Venus and the Moon are 45 degrees apart, forming a 45-degree aspect. Simple, right?

Aspects do not have absolute good or bad meanings. Many modern astrologers believe that square aspects can provide drive and ambition, especially when they integrate with other planets in the natal chart. In addition, if the birth time is accurate, you should also consider aspects between planets and the Ascendant and Midheaven; if the time is not accurate, it’s best to disregard these (the Ascendant and Midheaven are the cusps of the first and tenth houses and are highly time-sensitive).

In astrology, many angles have special meanings and can subtly influence an individual’s personality and life path. These angles can reveal where someone may express their strengths most fully, as well as where they might feel psychological pressure and tension. Pay particular attention to the 0-degree conjunction, 60-degree sextile, 90-degree square, 120-degree trine, and 180-degree opposition. If your natal chart includes these angular relationships, their effects on your temperament and destiny are significant.

Additionally, if your birth time is reliable, include aspects between planets and the Ascendant and Midheaven; if not, it’s best to set these aside (the Ascendant and Midheaven are in fact the cusps of the first and tenth houses and are strongly influenced by time).

120 Degrees and 60 Degrees

Both of these are favorable aspects, indicating a positive interaction between planets, with the 60-degree sextile being somewhat weaker. If you were born under such conditions, it’s naturally easier for you to express the positive qualities symbolized by those planets. These aspects suggest that the most likable parts of your personality often align with your talents. Strong performance tends to attract benefactors, support, and opportunities, helping you identify directions that suit your development throughout life. Your lucky colors can also be drawn from here. For example, if the Moon in your natal chart forms only 120-degree or 60-degree aspects with other planets, wearing Moon colors—such as silver, cream, or green—can remind you to express your empathy and keep good fortune flowing.

180 Degrees

This is considered one of the more challenging angles. On a circular chart, if two planets are 180 degrees apart, it often appears in one of the following six polarities:

• One planet in Aries and the other in Libra: you may vacillate between “self-interest” and “altruism.”
• One planet in Taurus and the other in Scorpio: you may struggle between “material possession” and “resource sharing.”
• One planet in Gemini and the other in Sagittarius: you may feel torn between “popularity, breadth of information, and variety” and “depth of knowledge and exploration.”
• One planet in Cancer and the other in Capricorn: you may be caught between “warmth, family” and “structure, career.”
• One planet in Leo and the other in Aquarius: you may waver between “self-importance, self-expression” and “community involvement, collective creation.”
• One planet in Virgo and the other in Pisces: you may swing between “service, duty” and “spiritual devotion, voluntary sacrifice.”

If your natal chart contains a 180-degree aspect, you may often feel conflicted, tense, and pulled between opposites—like a seesaw. Seeking balance becomes an important life task, and reaching that equilibrium marks times of growth.

90 Degrees

This is another challenging angle. Individuals with this aspect in their natal chart may feel blocked in certain talents. You might know that relaxed driving is most effective yet be unable to calm your nerves; understand that research is essential before investing yet still find yourself stuck; realize that cooking requires controlling heat yet fear the flame; want to write well but struggle to express yourself. Such patterns can arise from a 90-degree aspect in your chart. You may be acutely aware of these limitations, but they aren’t easy to adjust. What you can do is shift your focus to areas where you naturally excel—that is, the domains highlighted by your 120-degree and 60-degree aspects.

0 Degrees

This angle indicates that two (or more) planets are very close together, often in the same zodiac sign. As a result, your personality will be strongly colored by that sign.

That said, most planets are not positioned at exactly 0, 90, 120, or 180 degrees. When interpreting personality or events based on aspect angles, astrologers usually allow a small margin of error, or orb. For the four angles above, some set the orb at up to 8 degrees. Therefore:

• If two planets are within 0–8 degrees of each other, they can be treated as 0 degrees (a conjunction).
• If two planets are within 82–98 degrees apart, they can be treated as 90 degrees (a square).
• If two planets are within 112–128 degrees apart, they can be treated as 120 degrees (a trine).
• If two planets are within 172–188 degrees apart, they can be treated as 180 degrees (an opposition).

In principle, the closer the angle is to exact, the stronger the influence. So if both are considered 90 degrees, a 92-degree square will generally have a stronger effect than a 98-degree square.

If you want to know which aspects are present in your natal chart and how they influence your personal fortune, you can calculate them yourself or, more simply, visit specific websites to download a free chart. By checking the colors of the lines on the chart, you can quickly identify the relevant information.

If you’ve learned how to calculate angles between planets, try taking it further by using an astronomical calendar to find the positions of Jupiter and Saturn in 2010, then calculate how many degrees they are from each planet in your natal chart. Do any of the four major aspects appear? Next, look up related articles to compare and see what events those angles may indicate for you. Using this method, you can forecast your fortunes for the coming year and become your own astrological consultant.