Ascendant and chronobiology


One of the most important factors of a natal chart is the Ascendant or Rising Sign, which is the sign that was at the Eastern Horizon at the time of birth. It coincides with the Sun sign if the native was born at sunrise, if not, it is a different sign. An illustration is provided below. Keeping the Ascendant “Aries” fixed, the sun is in Aries at sunrise at approx. 06:00 AM. However, if the native has Aries ascendant and was born at noon, then the sun sign is Capricorn; if the native has Aries Ascendant and was born when the sun was setting in the West, the sun sign is the sign exactly opposite Aries in the Zodiac i.e. Libra.

In other words, the combination of the Ascendant / Sun sign provides information on the time of day when the native was born.

Time of birth

Why should the time of birth be considered so important? The time of birth is the very delicate moment when baby breathes for the first time i.e. when the automatic breathing centre and therefore the whole central nervous system is activated for the first time. Moreover, it is not until after birth that the immune system becomes fully activated together with the mechanisms that identify self vs non-self.
We know that all living things, including man, have internal biological clocks that regulate the function of the various systems of the body, optimizing their output according to biological needs throughout the day in a 24 h cycle. These 24 h changes are called “circadian rhythms” from the Latin circa (about) and dies (day). An illustration of some of the many changes recorded throughout the day is provided below.

It is reasonable to assume that the full activation of the central nervous system in the newborn child may differ according to the conditions of bodily functions at the time of day when it occurred.