You don't know your exact birth time: what you lose and where to find it

Almost everyone knows the day they were born. The time is another matter: it's known approximately, or as someone remembers it, or not at all. And it's the first place a birth chart gets stuck, because it isn't a decorative detail.

What the time decides, and what it doesn't

The date and place are enough to know where every planet was that day. Your Sun, your Moon, Mercury, Venus, Mars: all of that is settled without the time, give or take. The Moon moves fastest —it changes sign every two and a half days— so if you were born near one of those changes, the time does decide.

What only comes from the time is the rising sign: the degree of the zodiac climbing over the horizon of your birthplace, in that minute. And the rising sign is what orders the twelve houses, the map of which area of your life each planet falls into.

That's why two people born the same day in the same city, hours apart, have the same planets in the same signs and a completely different reading.

How far the rising sign moves in a few minutes

The Earth turns once in 24 hours, so the horizon travels all 360 degrees of the zodiac in that time: roughly one degree every four minutes.

"Roughly" is doing real work there. Signs don't all rise at the same speed: near the equator the difference is small, and the further away you are, the more it distorts. Some signs rise in under an hour, others take more than two. In practice: half an hour of error can move your rising sign into another sign, and a time rounded off at random makes it a coin toss.

Where your exact time is written down

Most reliable first:

• Your birth certificate. It's the document where the time was written down at the moment, not from memory. In many countries it's there; in others it isn't recorded at all. It's the first place to look.
• Hospital paperwork. Wristbands, discharge summaries, the baby book. They tend to turn up in boxes nobody has opened in twenty years.
• Whoever was there. Asking works, but ask well: instead of "what time was I born?" —which almost always returns a round number— ask what was happening around it. Whether it was day or night, whether they'd had lunch, whether they made it in time or arrived in the middle of the night. A time reconstructed that way is usually more honest than a remembered one.

If it doesn't turn up anywhere

That's not the end of the road, and here it's worth being straight instead of selling smoke.

You can generate your chart anyway. The planets and their signs will be right, and that's most of what gets read. What you won't be able to take seriously is the rising sign and the houses: don't ignore them, just don't build anything on top of them.

The usual convention when there's no time is to use noon, because it keeps the Moon's margin of error as small as possible. It isn't your rising sign: it's a chart being honest about what it doesn't know.

And if the data ever turns up, you generate it again. A chart doesn't expire.

Before you enter it

Two things that get overlooked and ruin a time that was actually exact:

• The place, not the country. Houses are calculated from the city's coordinates. Entering the capital when you were born two hundred miles away moves the calculation.
• The time as written, not corrected. Enter the time exactly as it was recorded, without adjusting it yourself for daylight saving or time zone changes. The calculation handles that from the date and the place; if you correct it by hand, it gets corrected twice.

If you already have the time, it takes a minute: enter date, time and place and see where your rising sign lands.

And if you're left wondering what exactly the rising sign is that the time defines, that's the other note: Sun, Moon and Rising: three things that aren't the same.