**Herong's Notes on Astrology and Horoscope** - Version 2.11, by Dr. Herong Yang

The Celestial Sphere Coordinate System

This section describes the celestial sphere coordinate system.

The fixed coordinate system on the celestial sphere is defined as:

- The north celestial pole (NCP) is defined as the intersection point of the north pole of the Earth and the celestial sphere.
- The south celestial pole (SCP) is defined as the intersection point of the south pole of the Earth and the celestial sphere.
- The celestial equator (CE) is defined as the projection of the Earth's equator on the celestial sphere.
- The latitude on the celestial sphere is defined in the same as the Earth's latitude.
- The longitude on the celestial sphere is defined in the same as the Earth's longitude.

The following picture provides a good illustration of the fixed coordinate system on the celestial sphere, http://www.astro.columbia.edu:

Table of Contents

Quick Introduction to Astrology

►Basics of Astrology and Astronomy

►The Celestial Sphere Coordinate System

The Celestial Meridian and Zenith

The Precession - Rotation of Earth's Axis

Introduction to Western Zodiac Signs

Horoscope and Horoscopic Astrology