Behind the scenes
Every chart on ORBIT is calculated from real astronomy, live, the moment you ask for it. Nothing is made up or copied from a list. Here’s where each part comes from.
01
type your date, time and place of birth.
02
finds your birthplace: its exact location and time zone.
03
works out the exact moment you were born, worldwide.
04
calculates where the Sun, Moon and planets were.
05
adds the signs, houses and angles, and explains them in plain words.
01 · Where you were born
When you type your city, ORBIT asks Open-Meteo, a free and open place-search service, for places with that name. Each result comes with the place’s exact position on Earth (latitude and longitude) and its time zone.
You have to pick your city from the list, so the place is always a real one. The city name you type is the only thing sent: never your date or time of birth.
In the code: js/astro/places.js
02 · The exact moment
“14:30 in Madrid” isn’t the same moment as “14:30 in Lima”, and clocks change with summer time, and countries have changed their rules over the years.
Your browser already contains the world’s time-zone history (the IANA time zone database). ORBIT uses it to find what the clocks read in your birthplace on your birth date, and turns your birth time into one exact moment that’s the same everywhere (UTC).
In the code: js/astro/time.js
03 · Where the planets were
Astronomy Engine is a free, open-source astronomy library by Don Cross. For that exact moment, it calculates where the Sun, Moon and each planet appeared in the sky, as seen from Earth. It’s accurate to about 1/60 of a degree, far finer than you could ever see on the wheel.
It runs inside the website itself, so your birth details are never sent anywhere to be calculated.
In the code: js/vendor/astronomy.js (the library) and js/astro/chart.js
04 · ORBIT’s own calculations
No birth time? Then there’s no Rising sign or houses, because they change every few hours. ORBIT leaves them out rather than guess. An approximate time? ORBIT shows every option that time could give.
In the code: js/astro/zodiac.js, js/astro/houses.js and js/astro/aspects.js
05 · Checked against real charts
ORBIT is tested against charts published by astrology websites (Astrotheme and Astro-Charts) for well-known people, including Barack Obama and Rafael Nadal. 83 automatic checks compare every planet, the Rising sign and the houses, plus tricky time-zone cases.
Each planet has to match within 2/60 of a degree (the fast-moving Moon within 3/60). The tests run before any change to the calculations is saved.
In the code: development/tests/
06 · The words
The meanings come from traditional astrology, written in plain words for people who are just starting out. They were drafted with the help of AI and edited by Salma, ORBIT’s creator.
Every reading is built from your own placements, using astrology’s simple formula: the planet is what part of you, the sign is how it shows up, and the house is where in your life. So two different charts always get different readings.
The positions are real astronomy. Their meanings are astrology: a tradition of interpretation, not science or prediction.
In the code: js/readings.js and the files in js/content/
07 · The sky now
“Your sky this week” and “Travel through time” use the same astronomy, run for today or any day you choose. ORBIT then compares that sky with your birth chart and explains the closest angles.
In the code: js/astro/sky.js and js/time-travel.js
08 · Your data
Your details are saved in your own browser. If you create an account, they’re also kept in Supabase, a secure online database, so they follow you to any device. Its rules let each person read and change only their own data.
You can download everything or delete it at any time on your Profile.
In the code: js/store.js and js/cloud.js