Most astrology apps fetch a paragraph from a server and charge you monthly for it. Zodiac Wheel carries a celestial engine and computes every answer on your device as you look at it. It runs natively on iPhone and on iPad, laid out for each rather than scaled up from the other.
Planetary positions come from the orbital elements published by NASA’s Jet Propulsion Laboratory, solved for the date you are asking about. The Sun, the Moon, sidereal time and the rising degree follow the algorithms in Jean Meeus’s Astronomical Algorithms. Nothing is fetched, nothing is looked up, and nothing about you is sent anywhere, because nothing about you leaves the phone in the first place.
Features
- The Wheel — the twelve signs around a wheel of the year, a hand at the Sun’s true position, and every body standing at its own degree
- A shuttle that runs the sky — drive time forwards and backwards, from an hour a second to a season a second, and let go to return to the present. Watch Mercury slow, stop and turn
- The Sky — every aspect in force with its exact angle and orb, whether it is closing or separating, and every retrograde with the dates either side
- Birth charts — from a date, a time and a place, drawn round with the houses, the angles and the aspect web
- Whole Sign, Placidus or Equal houses, whichever tradition you work in
- Historical time zones handled properly, so a birth in a daylight-saving week decades ago resolves to the right hour
- Several charts saved, and a chart shared as a composed card rather than a screenshot
- Reference — twelve signs, ten bodies, twelve houses and five aspects, each with what it signifies, searchable and written to explain rather than to predict
- A home-screen widget in two sizes, carrying the sign the Sun is in and the date it crosses into the next
- Engraved plates for every sign and every classical deity, in the manner of a seventeenth-century celestial atlas
- Tropical or sidereal, and a light or dark ground
- Universal — on iPad the birth chart runs two columns, with the wheel at full size beside the angles and the whole placement and aspect table in view at once
- No account, no subscription, no adverts, no tracking and no analytics
About the Numbers
Accuracy in this category is usually asserted. Here it is checkable.
Zodiac Wheel’s house cusps have been tested against the Swiss Ephemeris, the reference engine the professional programs are built on, across five hundred charts spanning 1900 to 2050 and eighty-nine degrees of latitude either side of the equator. The Placidus algorithm agrees to four thousandths of a second of arc. The angles agree to within about a minute and a half.
A sign is thirty degrees wide. Any real error in a birth chart is in the birth time, not in the arithmetic — four minutes on the clock moves the rising degree by a whole degree.
Placidus, incidentally, has no answer inside the Arctic and Antarctic circles, where some degrees of the zodiac never rise at all and there is no daily climb to divide into three. Zodiac Wheel says so on the chart and falls back, rather than printing something that merely looks right.
Privacy
No ads. No tracking. No analytics. No subscriptions. No in-app purchases. No account.
The app makes one network request and only if you ask it to: turning a typed birth place into coordinates. You can type the coordinates yourself instead and never touch the network at all. Full detail in the privacy policy.
Support
Need help with Zodiac Wheel? Whether you have a question, want to request a feature, or need to report a problem:
- Ask a question — get help using the app
- Report a bug — let us know if something isn’t working
- Request a feature — suggest an improvement
You can also browse existing issues to see if your question has already been answered.