Astrocartography · Birth-time guide
01 · Recorded time
Use the recorded local time and birthplace. Check AM/PM and whether the time was rounded; an exact-looking entry can still be uncertain.
Create your free map02 · Approximate time
Keep the uncertainty visible. Enter the earliest and latest plausible times on the same birth date, then compare the resulting lines.
Compare possible times03 · Unknown time
There is no supported personal line to select from a whole day. Look for a record, or use the worked example below to learn without inventing a time.
Look for your birth timeAstrocartography plots where a planet was rising, setting, overhead or beneath the Earth at a particular moment. Those are its Ascendant (AC), Descendant (DC), Midheaven (MC) and Imum Coeli (IC) lines. Changing that moment changes which places meet those conditions.
Saturn and Pluto move slowly through the zodiac, but the Earth keeps rotating beneath them. Their geographic lines move too. There is no separate set of Sun, Venus, Jupiter or outer-planet lines that bypasses birth time.
As a rough guide, MC and IC meridians move about 15° of longitude in an hour, or 1° in four minutes. The exact change depends on the planet; the distance in miles also depends on latitude. A single fixed distance cannot describe everyone’s uncertainty. Astrodienst explains the effect of Earth’s rotation on line positions.
Choosing noon therefore creates a map for a hypothetical noon birth. It does not average the day’s possible maps or make the displayed cities reliable. The introduction to astrocartography explains the method; our map-reading guide explains the line labels and interpretations.
This calculated example holds the date and location fixed and changes only the time. Start with Saturn, then try Pluto or the Sun. The solid line moves as you change the candidate time. These are illustrative calculations, not a chart for you.
Worked example · not your birth chart
2000-01-15 · 12:00–13:00 · Europe/London. Move through 9 sampled times to see how the same line moves. This example uses 15 January 2000 in London, with no personal birth data.
The Saturn MC line moves about 15.0° of longitude across these sampled times. This planet’s geographic line depends on time.
Each line is conditional on the selected time. These samples do not identify your birth time, cover every possible position, or assign a probability to a city. AC/DC curves are sampled every 2° of latitude; all lines are clipped at 60° north and south.
| Local time | UTC offset | Line longitude |
|---|---|---|
| 12:00 | UTC+00:00 | 104.39° |
| 12:08 | UTC+00:00 | 102.39° |
| 12:15 | UTC+00:00 | 100.63° |
| 12:23 | UTC+00:00 | 98.63° |
| 12:30 | UTC+00:00 | 96.87° |
| 12:38 | UTC+00:00 | 94.87° |
| 12:45 | UTC+00:00 | 93.11° |
| 12:53 | UTC+00:00 | 91.11° |
| 13:00 | UTC+00:00 | 89.35° |
For your own approximate time, enter a range supported by your records or recollection. “Between 08:00 and 10:00” is more honest than selecting 09:00 and treating it as exact. If you only know “morning,” that word needs a plausible time interval before a comparison can be meaningful.
The free comparison samples up to nine times, including the interval’s endpoints, and shows all supported planets and angular lines. It helps you see sensitivity to time. It does not narrow your birth time, supply a continuous uncertainty band, or certify that a city is suitable throughout the interval.
Compare your approximate birth timeAdoption, family circumstances or unavailable records can leave this question unresolved. You do not need to pursue records that are inaccessible or distressing. Keep the time marked unknown. The place-archetype quiz offers a separate way to reflect on environments you prefer; it does not calculate planetary lines or replace birth data.
In astrology, rectification means proposing a birth time by comparing candidate charts with a person’s reported life events. The result is an interpretation-dependent estimate. It should not be described as independently verified merely because the chart seems to fit.
If you consult someone about it, ask what range they considered, what information they used, what uncertainty remains, and whether another time also fits. Keep the proposed time and its source alongside the original record. Our calculator and quiz do not perform rectification.
Our personalised location report requires a known birth time and does not include automatic rectification. If your time remains approximate, the free comparison is the appropriate next step.
Astrocartography is an astrological interpretation, not an established method for predicting how a move will turn out. Even a correctly calculated map should sit alongside practical considerations such as work, housing, relationships and access to care.
Noon charts, approximate times, outer planets and reports.
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Contact Support →The worked example uses Swiss Ephemeris in Moshier mode, with 15 January 2000, London, and nine times from 12:00 to 13:00 UTC. MC longitudes are calculated from planetary right ascension and Greenwich sidereal time. Swiss Ephemeris documentation describes those astronomical quantities.
Further references: Astrodienst’s map FAQ and the CDC vital-records directory. The example compares calculations; it does not validate astrological predictions.