Interactive Educational Tool

What is the Celestial Equator? Ecliptic, Declination and Paran Guide

Explore the concepts from the Fixed Star Calculator interactively. Toggle layers to see ecliptic longitude, declination parallel and paran relationships.

Drag to rotate
Celestial Equator
Imagine extending Earth's equator into the sky. That is the celestial equator. Whether a star sits above (+) or below (-) the equator is measured by its declination.
Blue line = celestial equator. Horizontal circles = declination circles.

Key Concepts in Fixed Star Astrology

Celestial Equator and Declination

The celestial equator is the projection of the Earth's equatorial plane onto the celestial sphere. How far above (+) or below (-) this equator a star or planet sits is measured as its declination.

Ecliptic Longitude and Latitude

The ecliptic is the path the Sun traces across the sky throughout the year. The 12 zodiac signs are arranged along this line. A star's ecliptic longitude is determined by drawing a perpendicular line from the star to the ecliptic.

Declination Parallel

When two celestial bodies share the same declination they are in parallel. Unlike ecliptic longitude, parallel does not rely on projection and reflects true geometric proximity.

Paranatellonta (Paran)

A paran occurs when two celestial bodies simultaneously occupy angular points such as the horizon, meridian (MC/IC) or other angles. Paran is observer-location dependent.

How to Use This Tool?

You can drag to rotate the interactive celestial sphere above. Toggle the 5 layers on and off to explore each concept. This tool is designed to visually teach the concepts found in the Fixed Star Calculator.