How exact
is it?
Every chart is calculated in your own browser with Astronomy Engine, an open-source astronomy library. The positions are apparent places on the true ecliptic of the date, the way astrologers' software gives them.
Chiron, Ceres, Pallas, Juno and Vesta come from tables made with NASA JPL Horizons. The true node follows the Moon's real orbit, and Lilith is the mean lunar apogee.
We compared 20 charts with the Swiss Ephemeris, the reference most astrology software is built on. An arc-second is 1/3600 of a degree, far below anything a chart reading can see.
Seven house systems are drawn: Placidus, Koch, Regiomontanus, Campanus, Equal, Whole Sign and Porphyry. Above the polar circles Placidus and Koch cannot be drawn, so Porphyry is used.
Questions
Tick “Unknown” next to the time and we calculate for noon. The planets will be right to within a few degrees for the Moon and almost exactly for the rest. The rising sign and the houses depend on the exact minute, so we show them with a clear note that they are a guess.
Five pages. The wheel, your chart at a glance, every planet and point with its sign, house, speed and dignity, the full aspect grid with orbs, all twelve house cusps, and your element and mode balance.
The sky turns a full degree every four minutes. Ten minutes off moves your rising sign by about two degrees and every house cusp with it. Your birth certificate is usually the best source.
Yes. The file is vector, so it stays sharp at any size, with a 3 mm bleed for print shops. It prints well at home on A4, and any photo lab can do A3 or 50×70.