Astrology
Ephemeris
Direct answer
Ephemeris: An Ephemeris is a table or data source showing planetary positions over time. Astrologers use it to calculate natal charts, transits, returns, and historical sky conditions.
An Ephemeris lists planetary positions by date and time.
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At a glance
- Also called
- planetary table
- In astrology
- An ephemeris usually lists zodiac longitude, latitude, declination, speed, stations, retrogrades, and sometimes house or asteroid data depending on the source.
- Found in
- Astrology
- Related
- Birth Chart, Ascendant, House Ruler, Planetary Position
An Ephemeris lists planetary positions by date and time.
A structural orientation; exact placements depend on the chart or technique being discussed.
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What sets Ephemeris apart
An ephemeris is a day-by-day table, and the word is the Greek ephemeris, daily. Printed editions give the positions at a fixed hour, usually 0h Universal Time, so a chart for another hour needs interpolation, which matters most for the Moon, who covers 13 degrees a day. Regiomontanus printed an ephemeris at Nuremberg in 1474, covering 1475 to 1506. Modern software draws on computed models such as the JPL development ephemerides and the Swiss Ephemeris.
- Plural: ephemerides
- Columns: longitude, latitude, declination, daily speed, with stations and node positions
- Fixed hour: usually 0h Universal Time, with positions between filled in by interpolation
- Sidereal time: a column for it, which the houses and the Ascendant are worked out from
- Regiomontanus: Ephemerides printed at Nuremberg in 1474 for the years 1475 to 1506
- Earlier tables: the Alfonsine Tables of Toledo, from the 1270s, gave rules for computing positions
Often mistaken for something else: An ephemeris lists where the planets are. An almanac or calendar adds dates and events, and a natal chart is one calculation made from an ephemeris.
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The Book of the Sky
How people learned to read the sky, from Babylon to the day you were born.
The story behind Ephemeris
Ephemerides have been essential to astronomy and astrology for centuries and are now often embedded inside software.
The spiritual meaning of Ephemeris
Spiritually, Ephemeris keeps symbolic interpretation accountable to actual sky calculation.
Why Ephemeris matters
Ephemeris matters because interpretation depends on accurate sky positions. Before software, astrologers relied on ephemerides to know where planets were and when aspects became exact.
Ephemeris in practice: an example
To find a Saturn return, an astrologer checks when transiting Saturn returns to the natal Saturn degree in the ephemeris.
Where readings of Ephemeris go wrong
A common error is to interpret from an ephemeris without time zone, zodiac system, and calculation context.
Sources and editorial method
This entry summarizes the tradition in the Almanac's own words; where no source is listed, it is an editorial summary rather than a primary text, and symbolic readings are named as the tradition's, not as fact.
- Source
- The Great Almanac Dictionary
- Category
- Astrology
- Aliases
- planetary table
- Last updated
- 2026-09-26
Check today's sky positions
Ephemeris in a book is one thing; Ephemeris in your own birth chart is your life. The Oracle casts your real chart and tells you what it means for your love, your work, and your year ahead, in conversation. It opens with the 7-day Seeker trial.
Speak with the OracleHow Ephemeris lives in your own chart across your year, in love, in work, in timing, is written in the Cosmic Codex: the whole year, once. Open the Cosmic Codex
Related terms
More in Astrology
- Heliacal Rising
- Lot of Love
- Nadir
- Radical Chart
- Splay Chart Shape
- Zodiacal Aphesis
- Biblical Astrology
- Davison Chart
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Common questions
What is an Ephemeris?
An Ephemeris is a table or data source showing planetary positions over time. Astrologers use it to calculate natal charts, transits, returns, and historical sky conditions.
Where does an Ephemeris come from?
Ephemerides have been essential to astronomy and astrology for centuries and are now often embedded inside software.
What does an Ephemeris mean in astrology?
An ephemeris usually lists zodiac longitude, latitude, declination, speed, stations, retrogrades, and sometimes house or asteroid data depending on the source.
What does an Ephemeris look like in a birth chart?
To find a Saturn return, an astrologer checks when transiting Saturn returns to the natal Saturn degree in the ephemeris.
What does an Ephemeris mean spiritually?
Spiritually, Ephemeris keeps symbolic interpretation accountable to actual sky calculation.
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