Astronomical Basis for Astrology.

The Earth’s Structure:

Imagine the earth as a giant sphere spinning on an invisible axis, like a top spinning on its tip. This axis runs from the North Pole to the South Pole, passing through the center of the earth. Additionally, there’s an imaginary line encircling the earth horizontally, known as the equator, dividing the planet into two halves: the northern hemisphere and the southern hemisphere. To pinpoint specific locations on the earth’s surface, we use latitude and longitude coordinates, much like a grid system. Lines of latitude run parallel to the equator and indicate how far north or south a location is, while lines of longitude, running from pole to pole, indicate how far east or west a location is from a reference point.

Meridians and Celestial Sphere:

Meridians are imaginary lines connecting the North Pole to the South Pole, much like the lines of longitude on a globe. They help us map locations on the earth’s surface, with the prime meridian passing through Greenwich, England, serving as the reference point for measuring east-west distances. Now, imagine extending this grid into space infinitely. This celestial sphere concept helps astronomers map the positions of stars and planets relative to the earth. The celestial equator is an extension of the earth’s equator into space, while meridians on this celestial sphere correspond to terrestrial longitudes.

Declination and Right Ascension:

Declination and right ascension are celestial coordinates used to locate objects in the sky. Declination is similar to latitude on earth and measures how far north or south a celestial object is from the celestial equator. Right ascension, on the other hand, is akin to longitude and measures the eastward distance of an object along the celestial equator from a fixed reference point, such as the vernal equinox. Together, these coordinates help astronomers precisely locate stars, planets, and other celestial bodies in the night sky.

Ecliptic and Seasons:

As the earth orbits the Sun, it appears that the Sun moves across the sky along a path called the ecliptic. This path is inclined at an angle of about 23.5 degrees to the celestial equator. The points where the ecliptic crosses the celestial equator mark the vernal equinox (around March 21st) and the autumnal equinox (around September 23rd). These equinoxes signify the beginning of spring and autumn, respectively, and are characterized by equal lengths of day and night worldwide. The tilt of the earth’s axis relative to its orbit around the Sun causes the changing seasons. During summer solstice (around June 21st), the northern hemisphere is tilted toward the Sun, resulting in longer days and shorter nights. Conversely, during winter solstice (around December 21st), the northern hemisphere is tilted away from the Sun, leading to shorter days and longer nights.

Horizon and Meridian:

The horizon is the imaginary line that separates the earth from the sky when viewed from a specific location. It varies depending on where you are on the earth’s surface. The zenith is the point directly overhead, while the nadir is directly beneath your feet. The meridian is an imaginary line passing from the north to the south through the zenith and the nadir. It serves as a reference for determining the positions of celestial objects in the sky, much like the prime meridian does on earth.

https://commons.wikimedia.org/wiki/File:Celestial_sphere_with_ecliptic.svg.