Sun.Moon.Rising.

Your Big Three are the signs of your Sun, your Moon and your Rising sign (the Ascendant). The Sun describes your core identity, the Moon your emotional needs, and the Rising sign the way you meet the world and the first impression you make. Together they give a far more personal picture than a Sun sign on its own.

The Rising sign changes roughly every two hours as the Earth turns, so without a time it cannot be known. The Moon changes sign every two to three days, so on some birthdays it changes sign partway through the day. Your Sun sign and most planets do not need a time at all.

Yes. Tick "I don’t know my birth time" and you get your Sun, your Moon (with a note if it changed sign that day) and every planet, without houses or a Rising sign. Birth certificates in many places list the time, and a parent or relative may remember it roughly.

Planet positions come from an astronomical model accurate to well under a degree, and your birth place sets the time zone, including historical daylight saving rules. If you are born on the edge of a sign, a few minutes either way can matter, so an accurate birth time helps.

Placidus, the most widely used system in modern Western astrology, with whole sign houses as the fallback for births far north or south, where Placidus does not work.

No. The chart is worked out in your browser, so your birth date and time are never sent to us. The place search only sends the letters you type, to find matching towns. Nothing is stored unless you choose to email yourself the chart.

Astrology is a symbolic language, not a science, and nothing here predicts events. Many people find it a useful mirror for thinking about themselves and the people around them. Read it that way, for entertainment.