How your birth chart is calculated
Universe DMs works out your chart from the minute and place you were born, then compares it with the sky every day. This is what goes into it.
Your birth moment, in the right time zone
We turn your birth date, time and place into one exact moment in Universal Time. Time zones and summer time have changed many times over the last century, so we use the rules that applied in your birthplace on that date, from the IANA time zone database.
Planet positions from NASA/JPL
The positions of the Sun, Moon, Mercury, Venus, Mars, Jupiter, Saturn, Uranus, Neptune and Pluto come from DE440s, the planetary ephemeris published by NASA's Jet Propulsion Laboratory. It belongs to the same family of data NASA uses to navigate spacecraft.
From those positions we place each planet in its zodiac sign, down to the degree.
Rising sign, Midheaven and houses
With an exact birth time we also calculate your Ascendant (rising sign) and Midheaven, and divide the sky into twelve houses with the Placidus system, the most widely used house system in Western astrology.
These depend on the time far more than the planets do. The Ascendant moves into a new sign roughly every two hours, which is why they need an accurate birth time.
Aspects in your chart
We note the main angles between your planets: conjunctions, oppositions, squares and trines within 6°, and sextiles within 4°.
Every day: today's sky against yours
Each day we calculate where the planets are now and look for close aspects to your birth chart, within 1°. Those transits decide what a message can be about.
A measured image of the Sun from NASA's Solar Dynamics Observatory, refreshed every two hours, then picks the day's theme from them. Tap any message in the app to see the chart, the transits and the solar image behind it.
Questions
Is this a sun-sign horoscope?
No. A sun-sign horoscope is written once for everyone born in the same month. Universe DMs calculates your whole chart from your birth date, time and place, and compares it with the sky each day.
Which house system do you use?
Placidus. Houses need an exact birth time, so they are left out when the time is approximate or unknown.
Where does the planetary data come from?
From NASA/JPL's DE440s planetary ephemeris.
