The ephemeris

A table of where everything was, one page a month. This is the oldest object in astrology and the one underneath everything else on this site: before software, casting a chart meant opening one of these, finding the day, and interpolating by hand.

Every year we publish

From 1900 to 2050, which is 151 years and 1812 tables. The upper end is not a round number: it is where our checking stops. The Sun is held against NASA and JPL’s own values across 1650 to 2050, so that is where we stop too.

1900s

1910s

1920s

1930s

1940s

1950s

1960s

1970s

1980s

1990s

2000s

2010s

2020s

2030s

2040s

2050s

How to read it

An ephemeris is the oldest table in astrology: a row per day, a column per body, and in each cell the position of that body along the ecliptic. The figure is written as degree, sign, minute, so a cell reading 15♊︎23 is fifteen degrees and twenty-three minutes of Gemini. Sixty minutes make a degree and thirty degrees make a sign.

The Sun moves about one degree a day, so it changes sign roughly monthly. The Moon moves twelve or thirteen, so it changes sign every two and a half days and is the only column that visibly runs. Jupiter takes a year to cross a sign and Pluto takes about twenty, which is why their columns look almost still.

Before software, this is how a chart was cast: you found the day, found the next day, and interpolated by hand for the hour you actually wanted. That is still a good way to understand what a chart is, and it is still the fastest way to answer one question about one day.

What these figures are worth

Every number on this page is computed by the engine that casts the charts, not read from a bundled table, so what the positions are worth is what that engine is worth. The Sun is checked against NASA and JPL's own values across 1650 to 2050 and lands within an arcsecond. The Moon is within about six arcminutes. The planets are within a fifth of a degree of published ingress dates. The whole table of what we checked and where we are weakest is public, including the things we refuse to print.

Positions are geocentric ecliptic longitude at 00:00 Universal Time, which is the convention printed ephemerides use and the reason a figure here can be checked directly against one. Because it is tied to Universal Time, a position can sit a few hours either side of your own clock.

Eclipses are not marked on these tables. Our eclipse finder is reliable about the dates it gives and not yet reliable about finding all of them, so rather than print a list with holes in it we have left it off and put the eclipses we are sure of on the sky events pages.

The ephemeris you can page through · Eclipses and retrogrades ahead · Sun and Moon pairs · All the free calculators · What a placement means