The Celestial Meridian and Zenith
This section describes the celestial meridian and zenith.
The relative coordinate system on the celestial sphere is defined relatively to an observer on the Earth:
- The Zenith is defined as the line running the observer straight up to the sky reaching the celestial sphere.
- The Horizon is defined as the plan touching the observer and perpendicular to the Zenith line. The half celestial sphere above the
Horizon the visible sky of the observer.
- The Celestial Meridian is defined as the plan that running from the North Pole to the South Pole passing through the Zenith. The
Celestial Meridian divides the visible sky into two part: east part and west part.
The following picture provides a good illustration of the coordinate system on the celestial sphere:
The word "Meridian" is an ancient word meaning midday.
When telling time, we use the letters a.m. to indicate morning for ante meridiem, which is Latin for "before midday." We use p.m. for
post meridiem, or "after midday."
Table of Contents
About This Book
Quick Introduction to Astrology
►Basics of Astrology and Astronomy
What Is Astronomy
The Solar System
The Celestial Sphere
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
Horoscope and Planets
Chinese Astrology and Horoscope
Chinese Zodiac Animal Signs
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