The Chaldeans and Egyptians noticed that the planets and stars had an effect not only on our environment but on humans as well. To this, they developed the 'Decanates', based on the orbit of the sun around the zodiac. The Decanates constitute the foundation by which the individual birth or Natal chart is based upon.

They developed the 28 Lunar Mansions, or stations of the Moon, based on the 28 day orbit of the Moon around the earth, and noted its effects.

Chaldeans were masters in identifying and cataloging specific 'fixed' stars and their properties. Fixed, because unlike the planets, they do not orbit, but remain stationary.

In addition, they were expert mathematicians and astronomers. They had mapped the entire sky, developed an 18 sign zodiac and were able to accurately calculate the future positions of the planets and eclipses.

They had divided the elliptic orbit into 360 degrees, and attributed 60 minutes to each degree, and 60 seconds to every minute of a degree.

Great attention was given to the 12-year cycle of Jupiter through the signs, and the usage of the Ascendant or Rising Sign.

Chaldean Astrology was always performed in synergy with Chaldean Numerology, and were inseparable.

The only surviving cuneiform tablets on Chaldean astrology is a text called the 'Enuma Anu Enlil', which is a series of some 7000 predictive combinations on 70 cuneiform tablets, and the 'Venus Tablet of Amisaduqa'.

The Chaldean and Egyptian astrological sciences fused at one point, and became one science.