This video is not about, "If you are born between this and that date your personality is like this." It is meant for people with a fairly serious interest in astrology, and is especially important for practicing astrologers. This first part will explain how the 12 divisions of the zodiac are calculated, and will address the question of Tropical vs. Sidereal zodiac definitions.

What are the twelve signs? They are a way to measure space.

Space is like as a sphere all around us. The Sun and planets move through a narrow band anchored around the middle of that sphere. The twelve signs divide this narrow band into twelve discrete sections.

Why twelve? The easiest way to explain is to use an analog clock...