Planetary Positions Ephemeris

An ephemeris (plural: ephemerides) is a comprehensive astronomical table that displays the precise positions of celestial bodies—including the Sun, Moon, and planets—at regular intervals throughout time. Derived from the Greek word 'ephemeros' meaning 'daily,' ephemerides have been essential tools for astronomers and astrologers for thousands of years. In modern astrology, an ephemeris serves as the foundational reference for calculating birth charts, tracking planetary transits, and understanding the cosmic rhythms that influence our lives.

The ephemeris is indispensable for any serious astrological work. Without accurate planetary positions, it would be impossible to create natal charts, analyze transits, or time important events. Professional astrologers rely on ephemeris data daily to provide accurate readings and counsel. Whether you're a beginner learning about planetary movements or an experienced practitioner tracking complex transit patterns, the ephemeris is your essential roadmap to understanding celestial influences.

Our ephemeris uses Swiss Ephemeris data, widely recognized as the gold standard for astronomical accuracy in astrological software. Swiss Ephemeris is based on NASA JPL's Development Ephemeris (DE431), providing planetary positions accurate to within fractions of an arc-second over a span of 6000 years. This level of precision ensures that your chart calculations are as accurate as those used by professional observatories.

Key Components of an Ephemeris

• Planetary Positions - Exact zodiac positions showing the sign, degree, and arc-minute for each planet. These positions are geocentric (Earth-centered) and measured along the ecliptic—the apparent path of the Sun through the sky.
• Retrograde Periods - Clearly marked retrograde motion (℞) indicates when planets appear to move backward through the zodiac from Earth's perspective. Understanding retrograde periods is crucial for astrological timing and interpretation.
• Moon Phases - Daily moon phases from New Moon through Full Moon and back, showing the lunar cycle that influences emotions, rhythms, and timing in astrology.

Our ephemeris data is calculated using Swiss Ephemeris algorithms, ensuring professional-grade accuracy suitable for both personal exploration and professional astrological practice. The data covers the years 1900 to 2100, giving you access to historical positions for research and future positions for planning.

The use of ephemerides dates back to ancient Babylon, where astronomers meticulously recorded planetary positions on clay tablets over 2,500 years ago. These early ephemerides were used for both astronomical observation and astrological prediction. The Greek astronomer Ptolemy refined these tables in his Almagest, and Islamic scholars further improved their accuracy during the medieval period. The invention of the telescope and advances in mathematics led to increasingly precise ephemerides. Today, computer-calculated ephemerides like Swiss Ephemeris provide accuracy that ancient astronomers could only dream of, while serving the same fundamental purpose: tracking the movements of celestial bodies through time and space.

Reading an ephemeris requires understanding how planetary positions are expressed. Each position consists of three main components: the zodiac sign, the degree within that sign (0-29°), and the arc-minute (0-59').

Degrees represent the planet's position within its current zodiac sign. Since each sign spans 30 degrees of the 360-degree zodiac circle, a planet at 15° Aries is exactly halfway through Aries. The arc-minutes provide additional precision—there are 60 arc-minutes in each degree.

The zodiac sign shows which segment of the ecliptic the planet currently occupies. The Sun travels through all twelve signs in one year, while the Moon completes the circuit in about 28 days. Outer planets like Pluto can spend decades in a single sign, marking generational influences.

When you see the retrograde symbol (℞) next to a planetary position, it indicates that the planet appears to be moving backward through the zodiac. This is an optical illusion caused by the relative orbital speeds of Earth and the other planet, but it holds significant meaning in astrology for timing and interpretation.