Understanding Derivative Astrology

Learn How to Read the Chart from a New Perspective Using Derived Houses

Have you heard of derived houses and it just never made sense?

Derivative astrology is a tool that dates back to Hellenistic astrology. At its core, it's used to answer questions about specific topics that can be located within the birth chart. How you apply derivative astrology depends on the questions you're asking and the style of astrology you practice.

Hellenistic astrologers often used the Lots as their starting point, most commonly the Lot of Fortune. Modern astrologers, on the other hand, tend to use the Ascendant or a particular house related to the topic in question. For this article, I’ll be using modern examples.

What Are Derived Houses?

Derived houses are based on the idea of “turning the chart.” This means choosing another house in the chart to act as the starting point, as if it were the Ascendant. For example, if your question is related to children, you would turn the chart so the fifth house becomes the starting point. From there, you count forward to locate the area of life you're asking about, relative to that house.

This technique offers deeper insight into specific areas of life by revealing how the houses relate to each other from a new perspective. Derivation involves counting houses from the chosen starting point and interpreting their symbolic relationships.

A Simple Example: The Partner’s Income

For this example, we’ll begin with deriving to the Ascendant. In astrology, the seventh house represents the partner. This includes a romantic partner or spouse.

Now, let’s say you're curious about how your partner earns a living.
We know the second house represents income. When counting houses, we always start with the house in question as “one.” If you're using the Ascendant, the first house is one, and the second house is two.

But since we’re looking at the partner’s income and not our own, we begin the count at the seventh house, because that house represents the partner. The seventh house becomes house one. The eighth house becomes house two. That means your partner’s income is represented by your eighth house.

Or, to put it another way, imagine turning the chart so the seventh house sits where the first house normally is. From that point, the eighth house becomes the second house in this new arrangement. That’s where you would look for information about your partner’s income.

If you’re not quite following yet, that’s okay. This concept makes a lot more sense once you see a few examples in action.

In the above diagram, we are literally turning the chart. We’re placing the seventh house at the Ascendant and moving the eighth house into the position normally occupied by the second house. The zodiac signs would also shift accordingly with this change, which I’ll explain in just a moment.

You don’t have to physically turn the chart as long as you know where your starting point is. In fact, this can be easier since your zodiac sign placements don’t move. Instead, you simply count your seventh house as one and your eighth house as two, which now represents the partner’s second house of income.

Why do we do this? Because it helps us understand the zodiacal influence on the derived house. We’re looking for insight into how your partner might earn their money, and the sign on that house gives us clues.

Let’s use a chart for someone with Cancer Rising (which just happens to be me!)

With the diagram above, we can see that the partner is likely to have an Aquarian approach to earning their income. They may prefer working independently, but still focus on efforts that benefit society. Careers might include science, technology, social activism, or environmental work. They may also be drawn to creative roles like social media manager, content creator, copywriter, or consultant focused on innovation.

Other possible professions include data analyst, tech support analyst, electronic technician, or engineer. Aquarius energy also leans toward freelance work due to the freedom and flexibility it provides. Fields such as teaching, social work, humanitarian efforts, and activism are also possible, particularly when advocacy is involved.

Derivative in Real Life: Two Partners

I’ve had two major relationships, both with Capricorn men who were born just eleven days apart. I am a Cancer Rising.

My ex-husband was my first Capricorn Sun relationship that turned into a serious commitment. He was an electronic technician and owned his own business for many years, working erratic hours. Though he no longer owns that business, he’s still in the tech sector.

The second serious Capricorn relationship had several jobs over the years, but they all shared similar themes. He was an artist and worked as a copywriter and graphic designer for phone book advertisements. He was also an animal rights activist and once spoke in front of the Florida State Legislature wearing a bear costume to protest the lifting of the bear hunting ban in 2015.

Having Capricorn on my seventh house doesn’t mean I only date Capricorn men. I was also in a serious two-year relationship with a Cancer Sun man. At the time, I was working as a purchasing agent for electronic components. And yes, he was an electronic technician at the same facility.

Example: My Mother’s Health

Overall, my mother was quite healthy, but she did experience a few significant health issues in her life.

In the birth chart, the mother is represented by the fourth house, and health is found in the sixth house. Let’s take a look at how this played out in my chart using derivative house techniques.

If we use the “turn the chart” method, we would place my fourth house in the position of the first house. I’m a Cancer rising, but in this case, we now have Libra ruling the first house. That means my ninth house now becomes the sixth house. The zodiac sign that rules the ninth house in my chart would represent the energy of my mother’s health.

Remember, we don’t actually have to turn the chart. We can simply start at the fourth house and count six houses forward to find the one that represents my mother’s health. Once we’ve located that house, which is the ninth, we then look at the zodiac sign that rules it to get insight into her health.

As a Cancer Rising, Pisces rules my ninth house. Pisces is elusive, which means that health issues can be difficult to diagnose. With Pisces, you often see conditions that diffuse throughout the body, making them hard to pinpoint. These issues can be neurological in nature or related to fluids in the body. You might also encounter mystery illnesses, especially those affecting consciousness, movement (particularly involving the feet,) or perception. There can also be concerns around drugs or alcohol.

My mom began having symptoms in her early 40s. She struggled to concentrate and described her mind as feeling fuzzy. Even after a full night’s sleep, she felt exhausted. She visited her doctor several times, but because she always ate well and maintained an exercise routine, it was difficult to determine what was wrong. It wasn’t until she fell asleep at the wheel and flipped her car into a ditch on the way to work that more extensive testing was done.

She was eventually diagnosed with pernicious anemia, a condition where the stomach and intestines do not properly absorb vitamin B12 into the bloodstream. This disorder often shows up in individuals who drink heavily, but my mother rarely drank alcohol. Because of that, it wasn’t something her doctor initially screened for.

Eight years after the diagnosis, and after receiving regular B12 injections, my mother took up running. A few years later, with several marathons behind her, she needed minor foot surgery for an injury.

In her later years, my mother began experiencing confusion and memory issues. My parents did their best to keep this private, even though they were visiting doctors to figure out what was going on. Before I go further, I want to share my sister’s house placements, because both of our charts played a role in how my mother was eventually diagnosed.

The Role My Sister Played

My sister is an Aquarius Rising. Her fourth house is in Taurus, which represents our mother. Using derivative astrology, my mother’s health would appear in my sister’s chart in the sign of Libra.

Due to a conflict that happened, our parents did not speak to my sister or me for a year and a half. One of our cousins saw my mother at a gathering and contacted my sister, letting her know about her dramatic decline.

My sister and I went to our parents’ house. Even though my stepfather was angry about our arrival, my mother greeted us with joyful tears. She was thrilled to see us. But the woman we saw wasn’t the same mother we had known less than two years earlier. She didn’t lift her feet when she walked, she was forgetful, and she struggled to speak in full sentences. She also seemed much sweeter and kinder than she had been in the year leading up to the conflict. My sister and I quickly realized she was in the deep stages of dementia.

We worked to rebuild the bridge with our stepfather so we could see them at least once a month. We offered help and support, but it was often dismissed. During one of our joint lunches, my sister noticed our mother’s gait and told me she believed she had Normal Pressure Hydrocephalus (NPH,) the same disorder that was recently diagnosed in Billy Joel.

My sister is a physical therapist, and she has treated patients with NPH. With Libra ruling my sister’s ninth house, which represents our mother’s health, she had a balanced perspective and keen awareness of the symptoms. Together, we encouraged our stepfather to take our mom to another neurologist. She was officially diagnosed with NPH.

Venus, which rules both Libra and Taurus, is associated with aesthetic awareness, grace, and physical balance. Libra is highly attuned to imbalance in posture, symmetry, rhythm, and movement.

A shunt was placed in my mother’s brain to help drain the excess fluid. While it helped in the short term, a later fall prompted further testing. That’s when we learned she also had White Matter Disease, an aggressive form of dementia and cognitive decline.

When you look at both of our charts, with my sister’s ninth house ruled by Libra and mine ruled by Pisces, it becomes easier to see how these patterns played out in our mother’s health. I want to be clear: neither my sister nor I are medical doctors, and I do not recommend using astrology as a substitute for professional medical care. But derivative astrology can offer insight into a family member’s health that may otherwise be hard to recognize.

Example: Who Will My Son Marry?

Let’s shift to something a little more fun while continuing with the theme of derivative astrology.

We can use this technique to gain insight into my son’s spouse. In astrology, children are represented by the fifth house. My son married his wife in 2011, but if I wanted to explore who he might marry using derivative houses, I would look to the seventh house from the fifth, because the seventh always relates to partnerships.

So, starting at the fifth house and counting seven houses forward, I land on my eleventh house. In my chart, the eleventh house is in the sign of Taurus.

In this case, the eleventh house doesn’t represent my friendships or goals. Instead, it represents my son’s spouse.

My daughter-in-law is Taurus in nature, even though she doesn’t have any Taurus placements. Most of her placements are in the element of Earth, giving her the characteristics typically associated with Taurus. This is important to keep in mind. The zodiac sign will give the flavor of the situation, but it won’t dictate the actual zodiac sign of the other person.

She is stable, persistent, determined, and practical. She values comfort and loyalty, and has a calm, grounding presence that benefits my son. She’s also someone who stands firm in what she believes.

Their home environment is quite Taurian. Comfortable couches fill the living room and media room. The media room even has a mini-fridge for drinks, a table with an old-fashioned popcorn maker, and a snack display, much like what you’d find in a movie theater. Guests feel right at home when they visit.

Derived Houses and Horoscopes

Horoscopes are usually written using the rising sign for each zodiac, since the themes of each house will align more closely with the reading. However, with derivative astrology, you can also read your Sun and Moon signs to gain additional insight. When you read for your Sun or Moon sign, you’re essentially treating that sign as if it were on the Ascendant, and interpreting the rest of the chart in relation to it. It’s not as accurate as using your rising sign, but there’s often something in it that resonates.

In the 1990s, I had a subscription to Glamour magazine. Back then, I had no idea how horoscopes were written. Some astrologers write them based on the rising sign, while others place the Sun in the first house and derive a horoscope from that position.

With my Sun in Scorpio, I would naturally read that sign's horoscope. Sometimes it was spot on, but more often, it described my personality better than my current circumstances. What I began to notice, though, was that the horoscope for Cancer often resonated more, especially when it came to timing. Little did I know, this all had to do with derivative astrology.

Now that I write horoscopes myself, I know what to look for. If I’m reading a horoscope written by someone else, I always start with my rising sign, which is Cancer. Then I read the one for my Scorpio Sun and finally, for my Pisces Moon.

When it comes to timing, the rising sign is my focus. But to get insight into my state of mind or emotional well-being, I’ll look at Scorpio and Pisces.

Why Use Derived Houses When There Are Other Techniques?

There are many ways to interpret a birth chart or to track the timing of events. Derived houses offer something unique. They can add an extra layer of insight and even bring a sense of validation.

Validation is often dismissed in our culture, yet so many of us quietly wrestle with doubt and insecurity. In my case, with my mother’s health, I’ve struggled with guilt and the question of whether there was something more my sister or I could have done. I’ve studied her transits and progressed charts and have come to understand that her illness was going to unfold regardless of any external action.

What struck me most was seeing how her illness appeared in both my chart and my sister’s. That gave me a deeper level of validation. It also revealed that this experience was a spiritual lesson. It wasn’t just about my mother’s fate. It was about the dynamic between three women deeply connected on a soul level. Our relationship was layered, painful at times, and also healing. I can’t speak for my sister, but I know that my mother’s final year on Earth brought healing for me. My appreciation for her deepened, and it was already strong.

Whether you’re trying to understand your past, navigate your present, or explore what might lie ahead, derivative astrology can offer powerful clues. It can show you where to look, what to reflect on, and why certain patterns may be unfolding. Sometimes, turning the chart helps us turn the page. And with that, we find insight, healing, and peace.

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Want to explore the energies at play in your own chart? Schedule a reading with me at GrandTrineAstrology.com and gain insight or validation.