Only with at least a rough birth time. Between the polar circles, a date alone allows any of twelve signs, so with no time at all the rising sign stays open. A rough time window settles the sign if the whole window falls within one sign, but only an exact time and place pin down the degree.
Why doesn't a birth date give a rising sign?
The rising sign is the sign on the eastern horizon at your birth. Between the polar circles, the Earth's daily turn carries the whole zodiac across that horizon in about a day. So on the date alone, any of the twelve signs is possible.
- deg360
- h24
- sign30
360 ÷ 24 = 15 degrees an hour, so 1 degree every 4 minutes. 30 ÷ 15 = 2 hours for one sign.
On average, the rising sign changes about every two hours between the polar circles.
That average pace is 1 degree every 4 minutes, but the real pace changes with the sign and the latitude. Past about 66.5 degrees of latitude, north or south, the pattern breaks and some degrees of the zodiac never rise.
What can a rough birth time tell you?
It turns twelve possible signs into a shorter list, and sometimes into one. Take a sample birth in Chicago on 15 January 1998, known only as "some time in the morning", 06:00 to 12:00 local time.
| Rising sign | Local time |
|---|---|
| Capricorn | 06:00 to 07:37 |
| Aquarius | 07:37 to 09:01 |
| Pisces | 09:01 to 10:11 |
| Aries | 10:11 to 11:20 |
| Taurus | 11:20 to 12:00 |
Calculated with Astronomy Engine, an open-source library (version 2.1.19), for Chicago at 41.88° N, 87.63° W, tropical zodiac. Times are rounded to the minute.
"The morning" still leaves five possible rising signs. A window of 09:30 to 10:30 would leave two, Pisces or Aries. Any window wholly inside the Pisces row, about 09:01 to 10:11, such as 09:15 to 10:00, gives Pisces. That settles the sign, not the exact degree, which keeps moving through Pisces across the window. On this date in Chicago, Pisces and Aries each take about 70 minutes to rise, while Scorpio, rising in the early hours, takes about 2 hours 34 minutes.
What does a chart set to noon show?
A chart drawn for a default time, such as noon, still shows a rising sign, but it is one guess among the possible signs. For the Chicago sample, noon gives about 15 degrees Taurus. A birth at 06:00 the same day would have about 4 degrees Capricorn rising instead.
Your Rising sign and houses need your birth time and place. NinePath doesn't fill in a default time such as noon.
What this means for your day
For your day
Do
Write down any clue to your birth time as a range, such as 06:00 to 12:00.
Don't
Don't treat the rising sign of a noon chart as your own.
Questions people ask
Where can I find my birth time?
Start with written records: a birth record that lists the time, a hospital note or a family letter from the time. Treat a remembered time as a range, not an exact minute.
What can I still know without a birth time?
Your sun sign, unless you were born on a day the Sun changed sign. Your moon sign too, if the Moon stayed in one sign for your whole birth date.
Sources
- Wikipedia: Ascendant. The rising sign as the sign on the eastern horizon at birth, rising times that differ by sign and latitude, and the degrees that never rise beyond the polar circles.
- Wikipedia: Horoscope. Because of the Earth's rotation, the whole ecliptic passes through the ascendant in a day.
- Wikipedia: Central Time Zone. Central Standard Time is UTC-6.
- Astronomy Engine, version 2.1.19. The rising-sign times, durations and degrees for Chicago on 15 January 1998, tropical zodiac.