Why this exists
Most of us are handed a body and no instructions.
Mine took years to learn to read, and I did it the slow way — changing what I ate, changing when I ate it, sleeping properly for a month and then badly for a month, and writing down what happened. It was never really a diet. It was a long argument with myself, conducted mostly in a notebook. What came out of it was almost embarrassingly plain: whole food, eaten at regular hours, made me feel better than anything clever I ever tried.
Somewhere in the middle of all that I started reading the old Eastern material on food — Ayurveda first, then Chinese medicine — expecting it to be beautiful and useless. What I found instead was my own notebook, written down two thousand years before I got to it. Eat food your body recognises. Eat it warm. Eat it at roughly the same hour. Eat less when you are unwell, and more of the blood-building things once you have lost blood. Two traditions, thousands of kilometres and thousands of years apart, and a good deal of modern nutrition, all pointing the same direction.
That is the point where it stopped being about me.
Because the body all of that fits best is not mine. It is a body that runs on a monthly rhythm rather than a daily one — one that gets a week where everything feels possible and a week where very little does, and is generally expected to push through both without comment. A body most people are asked to manage with a calendar app and a guess.
I don’t have a cycle. There is no graceful way to say that on a page like this, so I will say it plainly and let you decide what it is worth. What I could do was build the thing carefully, and then take away every reason you would have to take my word for any of it. The maths is published and checkable. The sources are named. The things I cannot support are marked as things I cannot support. Your private notes never leave your phone. Trust me if you like — you shouldn’t have to.
The other half of this is the sky, and I will be straight about which category it belongs in. I do believe the movements of the moon and the planets touch us more than we generally allow. That is a view I hold, not a thing I can prove, and the app never pretends otherwise. What the astrology actually gives you here is a frame and a vocabulary for a month that is otherwise easy to live through as formless — three traditions looking at the same weeks from three directions. Not a mechanism. A way of paying attention.
So this is one place that holds your cycle, the moon and those three readings together, with food guidance from the two systems that have thought hardest about it.
It will not fix you. You are not broken. The most it can honestly promise is that the month stops arriving as a surprise — that the heavy week has a name and a reason before it lands, and the open week is one you can see coming and actually use.
That would have been worth a great deal to me. I hope it is worth something to you.
— The founder, The Ancient Cycle
What the app actually does
Four things, and nothing else:
- It works out where you are. From your period dates, it places you in a cycle phase. From your birth details, it casts three charts. From the date, it calculates the moon.
- It writes that up once a week. One reading, in three traditions, for the week you are actually in — not a generic description of a phase.
- It puts the two food traditions side by side. Ayurveda in one column, Chinese medicine in the other, and an explicit note where they agree. Where they disagree, you see both rather than a blended answer.
- It stays out of your way. Period dates are stored so the maths works. Symptoms and notes, if you log them, stay on your own device and are never sent anywhere.
The three traditions, and what each one is
Western astrology (tropical)
The zodiac used across Europe since Hellenistic times, anchored to the equinox rather than to the stars. Positions are geocentric ecliptic longitudes calculated from your exact birth moment converted to UTC. The founding text is Ptolemy’s Tetrabiblos, second century CE.
Vedic astrology (Jyotish, sidereal)
The Indian tradition, anchored to the fixed stars rather than the equinox. The gap between the two zodiacs — the ayanamsa — is currently a little over 24 degrees and grows by about one degree every 72 years, which is why a Western and a Vedic reading of the same chart usually differ by one sign. We use the Lahiri ayanamsa, the standard adopted by the Indian Calendar Reform Committee in 1955. The classical reference is the Brihat Parashara Hora Shastra.
Chinese Bazi (four pillars)
Not really astrology in the planetary sense at all — it is a calendar system. Your birth moment is expressed as four pairs of heavenly stems and earthly branches: year, month, day and hour. The year boundary is the solar term Lichun, around 3–5 February — not Chinese New Year, which is a lunar date and can be weeks away. Getting that boundary wrong shifts a whole year of the chart, so it is stated here. The classical references are Yuan Hai Zi Ping and San Ming Tong Hui.
The astronomy underneath all three
Planetary and lunar positions come from the astronomy-engine library, which implements the standard VSOP87 and ELP2000 series described in Jean Meeus’s Astronomical Algorithms. There is no proprietary “engine” here and no secret sauce — it is published maths, which is what makes the next section possible.
Three worked examples you can check yourself
If a calculator is right, it should agree with every other correct calculator. Below are three well-documented birth records — all rated AA, meaning the birth time comes from a birth certificate or public birth record — run through our free calculator, alongside the same figures from Astrotheme, which is an independent source with no connection to us.
Type any of them into the free calculator and you will get what is printed here.
Frida Kahlo — 6 July 1907, 08:30, Coyoacán, Mexico
| The Ancient Cycle | Independent source | |
|---|---|---|
| Sun | Cancer 13° | Cancer 13°23' |
| Moon | Taurus 29° | Taurus 29°43' |
| Rising | Leo 23° | Leo 23°36' |
| Nakshatra | Krittika, pada 4 | — |
| Four pillars | 丁未 · 丙午 · 丙辰 · 壬辰 | — |
Worth noticing: her Moon is seventeen minutes of arc from Gemini. Seven minutes of clock error either way and the answer changes sign. This is the honest reason birth time matters, and the reason we omit your Rising sign rather than guess it when you do not know your time.
Angelina Jolie — 4 June 1975, 09:09, Los Angeles, USA
| The Ancient Cycle | Independent source | |
|---|---|---|
| Sun | Gemini 13° | Gemini 13°25' |
| Moon | Aries 13° | Aries 13°05' |
| Rising | Cancer 28° | Cancer 28°53' |
| Nakshatra | Revati, pada 1 | — |
| Four pillars | 乙卯 · 辛巳 · 辛巳 · 癸巳 | — |
Three of her four pillars carry the same earthly branch — 巳, the Snake. In Bazi that concentration is the first thing a reader would comment on, and it is the kind of structure a generic sun-sign horoscope has no way to see.
Serena Williams — 26 September 1981, 20:28, Saginaw, Michigan, USA
| The Ancient Cycle | Independent source | |
|---|---|---|
| Sun | Libra 3° | Libra 3°49' |
| Moon | Virgo 20° | Virgo 20°24' |
| Rising | Taurus 3° | Taurus 3°10' |
| Nakshatra | Uttara Phalguni, pada 1 | — |
| Four pillars | 辛酉 · 丁酉 · 丁未 · 庚戌 | — |
How to check the parts the table leaves blank. The nakshatra follows from the Moon: take the tropical longitude, subtract the Lahiri ayanamsa for that year, and read off the 27 lunar mansions of 13°20' each. The four pillars follow from the Chinese solar calendar; the day pillar is a continuous 60-day count that any sexagenary day calculator will reproduce.
Where the traditions and modern nutrition actually meet
This is the part most wellness sites overstate, so here it is with the seams showing.
Where the overlap is real and well documented. Menstruation costs iron. That is measured, not interpreted, and both traditions independently prescribe blood-building foods during and just after bleeding — Chinese medicine explicitly in terms of Blood, Ayurveda in terms of rebuilding after depletion. The instruction and the physiology point the same way.
Where the overlap is plausible but thinner. Regular meal timing is an Ayurvedic instruction of long standing, and modern work on circadian rhythm and metabolism has begun to find reasons it might matter. “Begun to find” is the honest verb. Treat it as a reasonable habit with suggestive evidence behind it, not a settled result.
Where a tradition is a tradition and nothing more. The instruction to avoid iced and raw food during bleeding is consistent across both systems and is one of the more useful-feeling things in the app. There is no good modern evidence for it. It is in here because two traditions agree, not because a study says so, and the app labels it that way.
And the one everyone expects us to claim. We do not claim your period follows the moon. The largest analysis of this question — roughly 7.5 million cycles from 1.5 million users of the Clue app — found period start dates falling at random with respect to lunar phase. A much smaller long-term study from Würzburg, published in Science Advances, did find intermittent synchrony in individual women, more often under 35 and weakening with exposure to artificial light at night. Those two results are not really in conflict, but neither supports “the moon governs your cycle”, and we do not say it. The moon is in this app as a shared external calendar — something visible to everyone, moving on its own schedule, useful to read your month against. Not a cause.
Who checks this
Nobody, yet — and it would be easy to imply otherwise, so this is stated plainly.
The astronomy is verified: it is published maths, checked against independent sources, and the worked examples above are there so you can confirm it without taking my word for anything.
The wellness material is not clinically reviewed. It is compiled from the classical texts listed below and cross-read against modern nutrition, by one person, who is not a doctor, a dietitian, or a licensed practitioner of either tradition. If that changes — if a qualified reviewer comes on — this page will say who they are and what they reviewed.
Everything in the app is for reflection and general education. It is not medical advice, it is not a diagnosis, and it is not a substitute for a clinician. It is not a contraceptive and must never be used as one. If something about your cycle worries you — pain that stops your day, bleeding that soaks through hourly, periods that vanish or will not stop — that is a conversation for a doctor, not an app.
What this is built from
Ayurveda
- Charaka Samhita, Sutrasthana — diet, digestion and agni
- Vagbhata, Ashtanga Hridayam
- Vasant Lad, Textbook of Ayurveda (Ayurvedic Press)
Chinese medicine
- Huangdi Neijing (Suwen), chapter 1 — the seven-year cycles
- Giovanni Maciocia, Obstetrics and Gynaecology in Chinese Medicine (Churchill Livingstone) — the standard English clinical reference on menstruation in TCM
- Bob Flaws, A Handbook of Menstrual Diseases in Chinese Medicine (Blue Poppy Press)
Western astrology
- Ptolemy, Tetrabiblos (c. 2nd century CE)
Vedic astrology
- Brihat Parashara Hora Shastra
- Lahiri ayanamsa — Report of the Calendar Reform Committee, Government of India, 1955
Chinese Bazi
- Yuan Hai Zi Ping (淵海子平)
- San Ming Tong Hui (三命通會)
Astronomy
- Jean Meeus, Astronomical Algorithms, 2nd ed. (Willmann-Bell)
- astronomy-engine — the open-source library used for all planetary and lunar positions
On the moon question
- Clue, “The myth of moon phases and menstruation” — analysis of 7.5 million cycles
- Helfrich-Förster et al., Science Advances — lunar synchrony in long-term individual records
If you want to check rather than trust
Two links, both of which exist because trust should be optional:
- Verify it yourself in ten minutes — how to confirm, with your own browser’s developer tools, that your symptom notes never leave your device.
- The free calculator — no account, nothing stored, and the three charts above to check it against.
Cancel any time. Your period dates stay yours.