Aspects are pre-defined differences in degrees between two planets. The aspects most commonly used in astrology are set at increments of 30. Each aspect is said to have an angle, which expresses its size in relation to the rest of the zodiac wheel. A square, for instance, has an angle of 90 (out of 360); a trine has an angle of 120, and so on. The major aspects in astrology are:

ASPECT

MEANING

IN NATAL

IN TRANSIT

CONJUNCTION

Action: Positive

This is by far the strongest and most positive of all the aspects. It
means simply that one planet is at the same location in the heavens
as, or on top of, the other. A conjunction strengthens both
planets involved; each planet helps the other in a positive way.
In a natal chart, a conjunction imparts positive character traits and
strengthens the native’s interest in the subject matter ruled by both planets.
When a transiting planet makes a conjunction with (i.e., conjoins) a
natal planet, it brings a positive event into a person’s life
characterized by the planets, signs and houses involved.

SQUARE

Action: Negative

A square exists when one planet is at a right angle to another
planet. Both planets are separated by precisely three zodiac signs. A
square is a negative, or stressful, aspect which imposes an obstacle
in the native’s path.
In a natal chart, the square can indicate a negative character trait
or a recurring negative pattern characterized by the planets involved.
When a transiting planet squares a natal planet, it imposes
difficulty in the native’s life which is not easily resolved. Once
the transiting planet passes the square’s culminating point (at
exactly 90), however, a breakthrough, or release
of pressure, may be experienced.

TRINE

Action: Positive

A trine exists when the distance between two planets is one-third of
the zodiac wheel. Both planets are separated by precisely four zodiac
signs. A trine indicates harmony or a positive ‘joining
of forces’ with regard to the planets involved.
In a natal chart, a trine indicates where talents may lie or where
things may come easily to the native.
When a transiting planet trines a natal planet, it opens a window
of opportunity
or brings beneficial developments to the
native characterized by the planets, signs and houses involved.

OPPOSITION

Action: Negative

When two planets are precisely opposite each other, they are said to
be in opposition. An opposition always indicates integration or
resolution with regard to the planets involved.
In the natal chart, an opposition indicates where seemingly opposing
influences have been integrated into the native’s personality. This
integration, or resolution of difficulties, creates atypical
character traits or ways of looking at the world.
In the transiting-to-natal chart, an opposition presents the native
with a test or challenge characterized by the planets
involved. How the native meets the challenge and brings it to
resolution determines his or her level of success.