Guides
Time moves the local sky
Without birth time, houses and Ascendant are unreliable. What changes, and what you can still do.
What time changes
Planetary zodiac positions barely move in a few hours; Ascendant, Midheaven and houses do. Same day, different hour: often a different story.
How much it moves, in numbers
The Ascendant advances roughly one degree every four minutes and changes sign about every two hours. Half an hour of error is a quarter of a sign; two hours is a different Ascendant altogether, and with it a different division of all twelve houses.
The Moon is the only planet that also moves appreciably: about thirteen degrees a day, half a degree an hour. It can change sign overnight. Every other planetary position is stable within a single day.
Where to find it
In most of Europe the time is on the civil birth registration rather than on the family record book, and a full transcript can usually be requested online. In many other countries the birth certificate carries it directly.
If the registry does not have it, the domestic sources are left: a hospital wristband, someone's diary, a letter or a message from those days. Before giving the time up for lost it is worth asking two different people, because memories round to the nearest hour.
About rectification
There is a technique, rectification, that infers the birth time from events in a life. It is an astrologer's job: long, interpretive, and contested even among professionals.
We do not do it, and we would rather say so. What we sell is a verifiable calculation, not a hypothesis presented as a fact: if the time is not on record, the piece says so instead of inventing one.
If you do not know the time
Mark that in the configurator and we will flag that houses and Ascendant are not reliable, and you will see it in the preview before paying.
Some pieces (symbolic gifts built around Sun and Moon) still make sense; for accurate houses the time is essential. You can also order the print without the house grid, which is the honest way to let the object work without asserting what nobody knows.
Do you default to noon?
Only when time is missing, and we say so clearly. Better an honest preview than a misleading print.
Should I correct for daylight saving?
Do not correct it yourself. Enter the time exactly as the document states it, which is local time, and we resolve the zone that applied at that place on that date. Adjusting by hand is the most common way an hour of error gets introduced.
The hospital time is rounded to five minutes. Is that usable?
Yes. Five minutes is a little over one degree of Ascendant and will not change the sign unless the birth falls right on a boundary. What does distort a chart is a remembered «around nine» when it was eleven.