Overview
About ZodiScope
ZodiScope is astrology for self-discovery, built on exact astronomy. We calculate your birth chart for the minute and place you were born, from planetary positions built on NASA JPL data. Then we read every placement, house and aspect as the part of you it describes: how you work, how you relate to the people around you, and what today's sky is pressing on.
How we calculate
Planetary positions built on NASA JPL data
Every chart on ZodiScope, from your chart in the app to our free birth chart and birth-date compatibility calculators, gets its planetary positions from Swiss Ephemeris, the calculation library widely used in professional astrology software. Swiss Ephemeris is built on NASA Jet Propulsion Laboratory planetary and lunar ephemerides, the data JPL publishes on where the Sun, Moon and planets are over time.
Our calculation service runs the analytical ephemeris built into Swiss Ephemeris. The Swiss Ephemeris documentation gives its precision as better than 0.1 arcsecond for the planets and 3 arcseconds for the Moon, measured against JPL. One arcsecond is 1/3,600 of a degree. At that precision, the biggest factor in your chart is your birth time: your rising sign moves about one degree every four minutes, which is why we ask for your time to the minute.
We hold our own dates to the same standard. The sign changes, retrograde stations and other dates in our sky calendars are computed from, or checked against, NASA JPL's DE440 ephemeris.
The public compatibility calculator accepts dates without times. When the missing time could change a placement, it shows both possible signs and skips that comparison. The historical tables in our Taurus compatibility guides use a documented PyEphem date sample, with downloadable tables.
How we read your chart
Every placement, read as a part of you
Your birth chart is a map of where the Sun, Moon and planets were at the minute and place you were born, set against the 12 signs of the zodiac and the 12 houses. We read all of it. Every placement, house and aspect is described as the part of you it shows: how you're built, how you feel things, how you come across, how you get close and how you push back. Each line names the placement behind it, so you can see exactly where in your chart it comes from.
Want more context? Visit the ZodiScope Journal for deeper astrology insights.
Editorial responsibility and corrections
ZodiScope is the publisher responsible for the guides and tools on this site. We use automated tools to help draft and check content. Calculation notes and linked sources let readers inspect the basis of a claim; examples of couples in our compatibility guides are illustrative, not case studies.
Our compatibility material draws on Western tropical astrology. We distinguish calculated positions, traditional interpretations and evidence about real relationships. An astrological reading can offer a way to reflect, but it cannot establish someone's feelings or predict whether a relationship will succeed.
Found an error or a claim that needs a source? Send the page URL and the passage to hello@zodiscope.io.
What you can do today
Start with your birth chart. A free account gets your chart with a short reading for every placement.
Read your birth chart as the parts of you it describes, with every placement, house and aspect.
See how today's transits touch your own chart.
Compare your chart with a partner, a friend or anyone you save.
Follow daily, weekly, monthly and yearly horoscopes, draw a daily tarot card and ask questions about your own chart with Ask the Void.
iPhone and Android apps
We're building native apps for iPhone and Android. You can use ZodiScope now in your phone or computer's browser, with nothing to install.
Mission
Why we're building ZodiScope
People come to astrology to understand themselves, and a sun sign is only the starting point. Your birth chart records where every planet was at the minute and place you were born. We calculate it from planetary positions built on NASA JPL data, read every placement, house and aspect, and name the astrology behind each reading so you can see where it comes from.
FAQ
ZodiScope FAQs
Who is ZodiScope for?
Anyone who wants to understand themselves through their birth chart, whether you're new to astrology or already know your placements.
What makes ZodiScope different?
Two things. Your chart is calculated precisely, with Swiss Ephemeris built on NASA JPL data, for the minute and place you were born. And every placement, house and aspect is read as a part of you, like how you feel things or how you get close, with the placement named so you can see where each line comes from.
Do I need to know my birth chart to use ZodiScope?
No. Enter your birth details once and ZodiScope builds your chart for you.