Synastry is the comparison of astrological charts of two or more persons for purposes of assessing relationship.  The notes could also apply to persons, groups, and/or nations.  We will assume a basic understanding of aspects and houses.

There is no attempt to be exhuastive in these notes, however they contain the distillation of my experience in astrological synastry over the last 30 years.  Others have said a lot more on the subject, but this is what I have observed to work nearly all of the time over the years of observation.  Thus, we can make many very accurate predictions, encouragements, and well-considered warnings.


As with aspects in general, I give the most weight to the conjunction aspect in synastry, followed by the opposition, followed by the square, and then the other aspects weighted roughly equally.  The harmonious aspects of trines and sextiles are pleasant and helpful, but conjunctions and oppositions will be primarily where the most relevant action is in synastry.  

NOTE:  All aspects discussed here below refer to aspects *between* two parties' charts, not within an individual's chart.

CONJUNCTIONS show where two or more factors come together, and the sign where this occurs may indicate something of how that operates.   When I speak of "attraction" in relation to conjunctions, I refer to all kinds of interest between people, not just romantic attraction unless so specified.

OPPOSITIONS show where something about one person opposes the natural thrust or way of being of the other.  While oppositions can at times be complementary, and this is their optimal expression, most often they're stressful.  It's hard to move forward in life when one is being constantly opposed by another, when one's valid goals and life impulses are being sabotaged or thwarted.

SQUARES in synastry are pesky irritations that may never go away, but are not necessarily deal killers.  Squares often involve issues of "rightness," and emotional security that may be jeopardized by disagreements.  They also provide "spice" and other viewpoints to consider.

Both people's Suns, both Moons, both Venus, etc, in TRINE aspect (and in the same element of earth, air, fire, or water) add greatly to the potential for attraction, harmony, and agreement.  This is especially true of the luminaries (Sun and Moon).  

SEXTILE aspects add slightly to potential for communication and friendship, the possibility of building something together, and helping each other to achieve goals.  


Another's planets conjoining our Sun tend to get our attention and are hard to ignore.  There are issues of respect, power, admiration, authority, identity, self, health and vitality, well-being, self-confidence, radiance, and success.

Moon conjunct Sun: usually a strong attraction, lots in common, quick bonding and mutual understanding, openness to each other.  Even if not a tight conjunction, having Moon and Sun in the same sign in any degree is a very important aspect in synastry, and usually makes for high compatibility potential and attraction if not mitigated by other astrological and social/ethical/therapeutic factors.  Moon opposition Sun usually brings out the complementary nature of both, and is actually a positive aspect in relationship most of the time.

Mercury conjunct Sun: communication, ideas exchanged, ideas or approaches in common, lots to talk about, curiosity about each other.

Venus conjunct Sun:  pleasant, harmonious, helpful, possible attraction, admiration, goodwill, artistic and hobby interests in common.

Mars conjunct Sun: stimulating, possibly sexual, high energy, warring, and conflict.  The Mars person may perceive the Sun person as authoritarian, overbearing, or egotistical.  The Sun person may perceive the Mars person as argumentative, touchy, and stuck on differences.  Can be pleasantly stimulating in short bursts.  Sometimes works out harmoniously after an initial adjustment period of several months or years, if the parties learn to accentuate the positive and avoid pushing each other's buttons.  Can be good for the short term affair, and young women getting their early sexual experiences.  Young women often unconsciously seek out a man whose Sun is in the same sign as their own Mars for infatuation and early sexual experiences; these relationships almost never work out long term - too many disagreements, so it's good that young women have freedom to explore before making a choice for marriage, which will then be astrologically quite different from their earlier Sun-Mars choices.

Jupiter conjunct Sun:  a general blessing for both parties, and financially beneficial for the Sun person. A most auspicious aspect.

Saturn conjunct Sun: may begin as mutual admiration, but works to the detriment of the Sun person as time goes on. Good for intellectual pursuits and admiration among colleagues or peers, and for demonstration of mastery.  Both share high standards of excellence and ethics.  After a while the Saturn person will resist the Sun person's efforts and presence, and the Sun person will feel he can't do anything right, that even his very best is not good enough. Danger for the Sun person is loss of confidence, loss of vitality, loss of sparkle, golden life turned black, depression, regrets.  If criticism, intellectual games and oneupsmanship, or competition come into play, the Sun person can feel quite overwhelmed.  Can be a very deeply bonded connection, good for lifetime friendship, professional colleagues if not competing against each other, useful in cooperative ventures involving design and construction. Difficult in romantic or marriage relationships, and likely to put a damper or inhibition on sexual relations early on.

Uranus conjunct Sun:  The Sun person is stimulated on many levels, and slightly unnerved or made nervous by the presence of the Uranus person.  The Sun person can never fully relax in the presence of the Uranus person.  The Uranus person gives full permission for the Sun person to be an individual, bright person, entrepreneurial, spiritually aware, alive, and socially unconventional.  A stimulating relationship for friends and associates, but could be too hard on the Sun person's health and nervous system to be around the Uranus person all the time.  The Uranus person keeps the Sun person slightly off balance, which can be good at times for shaking up the status quo, troubleshooting, and a proverbial whack on the side of the head, but not all the time.  The Uranus person can make the Sun person more accident prone.

Neptune conjunct Sun:  A gentle, intuitive, refined, spiritual quality.  Shared spiritual or aesthetic interests. Telepathic rapport likely.  Relationship needs several reality checks if you're planning to do anything important together, as these two together can be unrealistic or ungrounded, over-optimistic and starry-eyed at times.

Pluto conjunct Sun: A powerful and possibly explosive influence, one that will be deeply transformative, and may involve life an death matters, with high intensity.  For the Sun person, it's like sitting on top of a rumbling volcano, and getting your deepest fears and subconscious stirred up where they were not before.  The Sun person is likely to feel a bit intimidated and uneasy around the Pluto person, yet there is the potential for deep telepathy and mutual empowerment.  The downside is power plays and manipulations by the Pluto person, and more intensity and pressure than the Sun person can handle long term.  Always intriguing, and not for the timid!

Chiron conjunct Sun:

The Chiron person will work magic in fascination, however the Sun person will usually have most of the power in the relationship.  The Chiron person however may prevail and succeed in life longer than the Sun person, should Sun ever reject Chiron.  Chiron bring surprises to the Sun person and tries to heal him.  If the other resists the opening for healing created by the Chiron person, the relationship breaks down, and the Chiron person may get rejected.  Chiron person will try to fascinate, and the Sun person wants to be noticed and admired.  Mutual admiration, high idealism, and openness to effective healing work best here. 


Planets aspecting our Moon deal with our natural open receptivity, needs for unconditional love and nurturing, emotional well-being, comfort, and security - very fundamental areas of life that must be taken into account. Most aspects to the Moon are similar to that of the Sun above.  

I would add that the Moon conjunct Mercury is one of the best aspects to have in any kind of relationship, fostering mutual interest and ease of communication.

Further, Mars conjunct the Moon tends to be both exciting and irritating, and a woman's Moon conjunct a man's Mars tends to result in stress and tears for her sooner or later, though there may be many other compatible factors.  Mars tends to come on too strong, does not take the Moon person's  needs into account, and fosters emotional pain.

MERCURY aspects have to do with communications and shared ideas.  Communication is a make-or-break factor in any relationship.

VENUS aspects lend harmony, idealism, pleasantries, ease, shared values, beauty, attraction, and sometimes love.

MARS aspects are exciting, stimulating, energizing, and sexual, but also provoking, willful, argumentative, disagreeing, loud, blaming, accusing, and sometimes violent.

JUPITER aspects are expansive, allowing, prospering, blessing.  In Jupiter oppositions, beware of bad judgment due to another's influence.

SATURN aspects are initially admiring, impressive, focusing, but later become squelching, denying, rejecting, oppressive, critical, narrow minded, blaming, accusatory, controlling, to the point of cold hearted cruelty - resulting in depression, apathy, hopelessness, depression, inhibition. Saturn tends to add longevity, glue, and concrete to relationships; Saturn conjunctions can be very difficult to get away from, yet they sap life force and often must be gotten away from even though that's the last thing the non-Saturn person wants to do.  Saturn aspects are what the Magi Society and as well as myself for many years have called "the heartbreak aspects."  No matter what the non-Saturn person does, it is rarely ever enough, rarely right, rarely good enough to come up to the Saturn person's expectations or standards.  More than speedbumps, the Saturn conjunctions especially all too often end up being disastrous despite the best efforts of the non-Saturn person.  Saturnian associations that remain on an intellectual or more formal level with minimized contact can succeed and retain the mutual admiration.

URANUS aspects are exciting and stimulating on many levels, awakening, enlightening, shocking, unconventional, surprising.  Situations can begin quickly, then are over just as quickly and mysteriously.  Useful for giving a broad variety of life experiences.  Uranus can be a shattering, explosive, and highly destructive influence if the Uranus person is so inclined.  Issues of the will, individuality, and the right to have one's own viewpoint qua viewpoint (rather than a focus on what is the truth of the matter or best way to do something after fairly weighing all input).

NEPTUNE aspects are idealized, beautiful, telepathic, spiritual, feel like "soul mates."  One's spiritual/religious path seems to be more symbolized by Neptune in synastry than Jupiter.  Possibility of falsehood, lies, non-confront, oblivion, or "rose colored glasses" on the material plane.

PLUTO aspects are powerful, intense, stir things up at a deep level, and encourage both parties to come into their full power in this lifetime.  Full honesty, authenticity, truth told with love in a way the other can receive, ethics, and effective therapeutic process are required to make the best use of Pluto.  Courage will be needed to hang in there.  Not for the timid!

The NORTH NODE person brings challenge, struggle, and effort to the other person's planet, whatever that planet represents.  Pay particular attention to the tight conjunctions!  Some people like the challenge, especially those who are bored, and others don't like it and consider North Node conjunctions a major bother and distraction from what they'd rather be doing.

The SOUTH NODE person brings ease, a sense of deja vu, and spirituality to the other person's planet, whatever that planet represents.  There may indeed have been a past life connection with the two of you regarding themes of that planet.  Sometimes the S.Node brings worldly losses with regard to the planet in question, but most of the time it is just an easy and comfortable connection, especially for older souls on the spiritual path.

CHIRON aspects bring attraction and fascination, also bizarre reversals, and this can go both ways or applied to both parties.  In the circumstances of ordinary life, Chiron aspects are a mutual monkey wrench in the works and often backfire.  The Chiron dance is a fascinating, if treacherous one, sort of like watching a slow train wreck - you can see it about to happen, but can't stop it, and can't take your eyes off of it.  There can be an obsessive, hypnotized quality to Chiron connections.  There's always potential for healing with Chiron, and where effective healing is rejected, things tend to go south and become chaotic, with new wounds inflicted.  There is often disagreement about what effective healing would consist in, and how to best achieve it, and therein lies the rub.  Chiron aspects eventually go toward both parties in a more involved relationship feeling very wounded and regretting ever getting involved with the other, whereas just the fascination aspect remains in a more detached yet humanly caring relationship.

JUNO aspects (conjunction) tend toward the parties wanting to cooperate and partner with each other.  Oppositions make partnering more difficult.

CERES aspects (conjunction) tend toward Ceres unconditionally loving and nurturing the other person.  Ceres conjunctions are very helpful in relationship. Stressful Ceres oppositions tend to thwart the Ceres person receiving the nurturing and unconditional love they need, a very bad situation.  Ceres is always positive and giving and a blessing (sort of like Moon-Venus-Jupiter all rolled into one), and having one's own Ceres stressed or opposed is not conducive to well-being or relationship longevity.

PALLAS aspects (conjunction) deal with the Pallas person's ability to plan, make goals, intuit, and strategize for himself or others, and how others contribute to or detract from Pallas' plans.  Oppositions deal with opposition to Pallas' plans or modus operandi, a key factor is the Pallas person has strong ideas about what he wants to do and how he wants to go about it.

VESTA tends to be an idealizing influence, shared ideals, and the warm fuzzy feeling and comraderie around shared values and ideals, and building something in life based on those.  Vesta oppositions deal with opposition to and frustration of one's ideals.

PART OF FORTUNE (conjunctions) act like a mild Jupiter influence.  I use only the conjunction for the Part of Fortune, as well as the angles (below).

ASCENDANT aspects (conjunctions) contribute to or detract from the Ascendant person's image in the world, how they project themselves in the world, and health.

NADIR aspects (conjunctions) contribute to or detract from the Nadir person's roots, comfort, and sense of security, what happens around their home environment, and may have something to do with end of life circumstances, or life and death circumstances.

MC aspects (conjunctions) contribute to or detract from the MC person's reputation, especially professional reputation, standing in the world, career path, professional openings and success, fame.

DESC aspects (conjunctions) contribute to or detract from the DESC person's way of being in relationship, how relationships go for them, not just with that individual but tends to spill over into all other relationships the person has as well.

VERTEX aspects (conjunctions) are similar to DESC aspects, sometimes even more important.  The Vertex point is not a planet, but is a mathematical point that functions as a very sensitive secondary descendant point.  Conjunctions to it by another's planets can be very significant in committed relationships of all kinds.

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WHERE PERSON X's SUN FALLS INTO PERSON Y's CHART is of paramount importance, and cannot be overemphasized, showing something of the ultimate gift, role, and emphasis that X is likely to play in Y's life.  

If X's Sun falls into Y's 1st house, this is good for Y's confidence, bringing him out of his shell, giving him carte blanche to be whatever he wants to be in life, "permission" to express himself freely.  Very good for all kinds of relationships.

If X's Sun falls into Y's 2nd house, the focus is on shared values, money, and possessions.  X will generally be an expensive proposition for Y, but what X brings to Y's life may be well worth it - only Y can be the judge of that.

If X's Sun falls into Y's 3rd house, it will generally be what I call "a big talking relationship," lots to talk about, shared ideas, short trips, books, new information, going here and there, cars and other vehicles, phone calls, more mental and sibling-like after any initial passion wears off.  

If X's Sun falls into Y's 4th house, X will tend to come to live with Y, they will manifest housing and real estate together, make a nest together, examine the dynamics of family relationships, and what makes for stability in life. Can be very good for marriage, this will tend to be a stable and reliable relationship long term, or at least Y will prefer it as such.  X becomes a "rock" of Gibraltar to Y.

If X's Sun falls into Y's 5th house, X is a lot of fun for Y and probably vice versa.  5th house is famous for love affairs.  If Y wants to have children, especially many children, X is a candidate mate to bring Y one or more children.  These two may enjoy hobbies, sports, artistic pursuits, special interests, or vacations together. Emphasis on the 5th house is about creativity, sponteneity, and celebrating the joys of life.  

If X's Sun falls into Y's 6th house, the emphasis for Y is on health, work/job, service to others, and the daily routine.  X can make a good employee, support staff, headhunter, health professional or colleague for Y, but 6th house marriages can be focussed on job, health, and the daily grind without much fun.  6th house friendships may focus on the healing process, workplace dynamics, and life transitions.

If X's Sun falls into Y's 7th house, one might expect this would be a great partnership or mate, however the interest may be short lived.  The parties bring each other new viewpoints to consider.  Taking a page from horary astrology, I've found that most of the time, with rare exception, X's Sun in Y's 7th house produces short-term relationship attractions, i.e. "the Sun burns out the 7th house" (horary).  X is usually the one to withdraw and lose interest, or burn out, even exhibit something of a "scorched earth" policy in leaving a relationship, or just withdraw quietly and mysteriously so as not to cause a fuss, even though Y would welcome having X around longer.  7th house relationships tend to burn out quickly.  Individual charts need to be examined for possible exceptions.  

If X's Sun falls into Y's 8th house, X brings deep psychological understanding and presence to Y's life.  There can be property caretaking, taking care of business and estate issues, awareness of life and death matters, rejuvenation, renewal, and a sense of the deep richness of life.  There are sexual overtones to the relationship that may or may not be acted out, are often kept at a level of subliminal awareness.

If X's Sun falls into Y's 9th house, X brings philosophical and religious issues, high mindedness, long distance communications and travel, books and publishing, opportunities to learn and teach and do marketing.  There is usually a broad tolerance of each other's viewpoints on a wide variety of subjects.  Mid-life and later-life marriages are often 9th house.

If X's Sun falls into Y's 10th house, the focus is on career openings and advancement for Y.  X makes a good mentor, door opener, introducer, boss, teacher, publicist, and champion for Y.  X is the more powerful and makes things happen in the world.  Y tends to admire X.  Because of the power disparity, normally the 10th is not the best house for marriage, which needs more of an equality to be fully successful.  10th house marriages may run aground when Y comes into his own power after being mentored by X for years.

If X's Sun falls into Y's 11th house, the focus is on friendship and more impersonal connection.  Perhaps the two parties met through a common organization they belong to. It's difficult to have much long term very close connection past good friendship with someone whose Sun falls into your 11th house.  The two can help each other achieve their goals and dreams in life, and make key introductions.  Later-life marriages are often 11th house, but early-life 11th house marriages seldom last as these need closer connection and more intimacy.  In retrospect, there can be a feeling of ships passing in the night with 11th house relationships, never quite fully connecting, or only briefly connecting.

If X's Sun falls into Y's 12th house, the focus is on metaphysics, psychology, spirituality, mysticism, intuitive development, the hidden undercurrents of life, causation, therapeutic process, and past lives.  Sometimes there is also an emphasis on long term health care, and complementary medicine.  It's rare to see anyone marry successfully into their 12th house unless there's a soul agreement for long term health care with one of the parties being chronically ill, or the parties mistake a feeling of familiarity that comes with shared past lives for a sign they should be together as mates - which is not necessarily true, is actually rarely true.

X's MOON THROUGH Y's HOUSES show an interest and a possibility that either party may entertain regarding the house in question and the relationship.  Mostly it shows how Y would like to be supported in life by X, how Y wants X to contribute to or be in his life.  However, some interest and a little exploration and action may be all that results, followed by something of a withdrawal by X.  Moon in the houses is not a big factor long-term in synastry, as a general rule, rather is more of a factor in relation to early interest and shorter term interaction.

X's MERCURY THROUGH Y's HOUSES bring conversation and learning in the area of X's Mercury sign and Y's house in question.

X's VENUS THROUGH Y'S HOUSES brings pleasure, grace, and ease to Y's house in question.

X's MARS THROUGH Y's HOUSES tends to bring a bit of stimulation, commotion and noise, conflict, action, and energy into Y's house in question.

X's JUPITER THROUGH Y's HOUSES tends to bring blessing, expansion, and prosperity short term and/or long term to Y's house in question.

X's SATURN THROUGH Y'S HOUSES tends to bring order, desire for organization and simplification, inhibition, a dampening effect, a minimizing, and an economy to Y's house in question.

X's URANUS THROUGH Y's HOUSES tends to bring an upsetting, surprising, unconventional, exciting, enlightening trend to Y's house in question.  There can be sudden changes for good or ill.  Sudden changes for ill are hard on Y's nervous system.

X's NEPTUNE THROUGH Y's HOUSES tends to bring an effect of  subtlety and telepathy to Y's house in question.  Fine distinctions are made via a more "right-brained" or gestalt awareness.

X's PLUTO THROUGH Y's HOUSES tends to bring a deep empowerment and potential for transformation, birthing a new world directly or indirectly.  When Pluto can be nurturing, intuitive, informative, mentoring, and uses power for mutual benefit and win-win, results for Y are very positive.

X's NORTH NODE THROUGH Y's HOUSES bring challenges, struggles, efforting to Y regarding the house in question.

X's SOUTH NODE THROUGH Y'S HOUSES tend to make things easy in that house for Y, though it does help for Y to get rid of the old and outworn, simplify in that area for best long-term results.

X's CHIRON THROUGH Y's HOUSES can be an attraction factor with regard to Y's house in question, but also a monkey wrench full of unpleasant surprises and reversals of what you'd expect, in terms of how can things go wrong and not in the desired or usual direction.  A lot of potential for healing and help, but also a possible minefield.  The houses with Chiron are not usually as upsetting as the conjunctions.

X's JUNO THROUGH Y's HOUSES can be a focus where partnership and connection operates well and often, and where Y expects to be supported by X.

X's CERES THROUGH Y's HOUSES can be an area the Ceres person wants to give unconditional love and nurturing to Y.  Simple and comfortable.  Do not take Ceres for granted! Validate Ceres, and life is grand.

X's PALLAS THROUGH Y's HOUSES can be an area the Pallas person wants to apply strategy, planning, intuition and design to Y's house in question.  

X's VESTA THROUGH Y's HOUSES can be an area where X gives Y unconditional support and trusts him to do the right thing in that area of Y's chart.


The composite chart is a different kind of relationship analysis technique.  It's the 3rd chart formed by taking the near midpoints of the parties' natal charts.  It can be read as a chart of the relationship.  I have found that major transits to the composite do apply, though this is highly controversial in the field.  For a study of composite charts, see Robert Hand's definitive book PLANETS IN COMPOSITE.