For a natal chart to be accurate, it is necessary to have a time of birth which is as accurate as possible. To calculate a horoscope the time of birth is converted to
Greenwich Mean Time, so it is important to know the time zone and to take into account whether
daylight saving timewas in force.
There have been relatively accurate registrations of all births in Germany since 1876. Before that time the church was responsible for recording all births. Since the end of the second World War, births have usually been recorded to the nearest minute. Any person interested in their own horoscope can and should get hold of his/her birth time from the registry office.
In the first half of the 20th century, the times were usually recorded to the nearest quarter of an hour. Only since the 1950s has it become common practice to record the time to the nearest minute or at least 5 minutes. The latter is generally sufficient for a fairly accurate horoscope except when the Ascendant, Medium coeli or any other
house cuspis close to the end or beginning of a sign because the Ascendant advances on average
one degree every four minutes - which of course also affects the position of the other house cusps.
It should now be obvious that in such a case the accuracy of the birth time is vital to accurately calculate the sign on the Ascendant or Medium coeli. A time accurate to within a minute is also important when usingpredictive methods. In order to achieve more accurate results, some astrologers use various methods of [[chart rectification]]. A more exact definition of the time of birth can be found in the article
Moment of Birth.
Cesarean sections and artificially induced births are frequently discussed topics, with one of the most common questions being whether the birth times are still as valid as those for natural births. There are differing views on the subject. Anyone who supports the idea that astrology (and therefore the birth process) has at its basis the idea that living organisms are sensitive to cosmic stimuli will have doubts about the time of any cesarean section which isn't part of the natural labour process.
This would mean that the times of births resulting from hormonal treatment or other kinds of medical interference would only be of limited validity for any natal chart.
Many people were born by cesarean section or had their times of birth influenced by other medical factors which would mean that astrologers already work with a large number of birth times they consider to be of limited validity. And it is important to remember that under difficult circumstances many so-called natural births are influenced by medical practice. This also applies to such natural methods such as homeopathic treatment, mammary stimulation or the combination of enemas and fasting.
In all of these cases an external human element is involved.
There is also a different line of argument which states that any methods used to help the birth process could be viewed as part of the cosmic plan, and that in the end each individual is always born at the appropriate time whether or not outside help was given.
