About the ephemeris

What the positions mean, and what they can and cannot tell you.

This site shows the daily positions of the seven points of the Diamond Astrology Ephemeris published by astrolab.nl. Every figure on this page was measured from the full source data, 1901–2050, and the identity of each point was checked against an independent ephemeris (see Where the numbers come from).

Reading a day

Each day gives one position for each of seven points. A position is an ecliptic longitude, an angle from 0° to 360° around the zodiac. It is shown the astrological way, as a sign plus degrees and arcminutes, which is the same angle cut into twelve 30° slices: 7°59′ Taurus means 7 degrees 59 minutes into the second slice, or 37.98°.

Here is 1 January 2021:

There is no location and no house information, and none is needed: ecliptic longitude doesn't depend on where you are. The same positions apply everywhere on Earth.

Coverage is unbroken: every calendar day from 1 January 1901 to 31 December 2050, 54,787 days in all, with no gaps.

The points move at very different speeds

• Black Sun and Diamond are effectively constant. They take only 142 distinct values in 150 years, roughly one change every 13 months. Black Sun stays between 11°14′ and 13°47′ Cancer across the whole range (Diamond mirrors it in Capricorn), moving about a degree in a lifetime.
• The two Liliths and Priapus genuinely depend on the date. Lilith (mean) moves a full degree every nine days.
• Lilith (corrected) is the volatile one. It can swing 1.5° in a single day and it reverses direction, because its correction term swings through ±12° every 206 days (see below).

Long-term drift. Persephone and Vulcanus are exact over the whole 150 years; the rest are measured over 2021–2025:

Motion markers

Each position in the source carries a motion marker, shown on the lookup page as ℞ for retrograde and St for a station. A position without a mark is direct.

Almost all of the variation is in Lilith (corrected): across 150 years it is direct on 31,588 days, retrograde on 23,098, and stationary on 101 days, which almost always fall on days with no motion at all. The only other marker in the whole dataset is a single station on Vulcanus, on 27 May 1913.

Two pairs of exact opposites

On every day in the data, to within floating-point precision:

• Priapus = Lilith (mean) + 180°. Priapus is the mean lunar perigee; Lilith is the mean apogee.
• Diamond = Black Sun + 180°. Diamond is the solar perigee; Black Sun is the apogee.

Priapus is opposite Lilith mean, not Lilith corrected. Against the corrected Lilith it is off by up to 12.3°, and not one day comes within 0.02° of opposition.

Where the numbers come from

The tables are output of Astrolab, the astrology program by E.O. Eshuis of Amsterdam, which computes positions with Swiss Ephemeris and JPL routines. Diamond Astrology descends from the Dutch Zwarte Lichten (Black Lights) school of George Bode, which in turn builds on the French astrologer Jean Carteret. That lineage accounts for every column. Each identification below was checked by recomputing the point independently and comparing it with all 54,787 days.

• Time of day. Every row is for 00:00 UT, truncated rather than rounded to the arcminute: the Swiss Ephemeris mean apogee at 0h UT is between 0′ and 1′ above the printed value on every day sampled. So a row is exact for midnight UT, and the fast points have moved up to about 46′ by noon.
• Black Moon Lilith (mean) is the mean lunar apogee, a standard mean orbital element, and matches Swiss Ephemeris to the arcminute. Priapus is the mean lunar perigee, mean Lilith + 180°.
• Black Moon Lilith (corrected) is not the osculating apogee that most software calls "true Lilith"; it differs from that by up to 19°. It is Bode's corrected Black Moon: the mean apogee plus a correction of about 12.3° × sin 2α, where α is the angle from the Sun to the mean Black Moon. The correction is zero when the Sun is conjunct or square the Black Moon and largest, 12°18′, at 45°, repeating every 205.9 days (half the Sun–apogee synodic period). Astrolab applies it from a table rather than the formula, so the curve has a flat top at exactly 12°18′ and half-degree steps near the zero crossings; it agrees with the formula within 3′ on a typical day and 45′ at worst. The ℞ and station markers follow the sign of this point's computed daily motion.
• Black Sun is the mean longitude of the solar apogee (Earth's perihelion), precessing 1.72° per century, and matches the standard mean-element formula in Meeus within about 2′. Diamond is Black Sun + 180°.
• Persephone (Carteret), formerly shown here as "point 6", is a straight line: exactly 1.000° per year, at 11°59′ Aquarius on 1 January 2000 and 0° Aries in 1688.
• Vulcanus (Carteret), formerly "point 7", is likewise a straight line at exactly 0.550° (33′) per year, at 10°41′ Gemini on 1 January 2000. The Dutch literature gives Vulcanus "about 33 arcminutes a year", "in Gemini since about 1980" and "23° Gemini in 2021"; the data give a Gemini ingress in mid-1980 and 22°14′ Gemini on 1 January 2021.

Persephone and Vulcanus are hypothetical planets proposed by Carteret in the 1950s. He fixed their positions from horoscope studies and published them in tabular form; George Bode introduced them to the Netherlands in De Nieuwe Planeten (1981). They have no physical orbit, which is why they never retrograde and why the single "station" marker on Vulcanus is only a day on which its rounded motion was zero. Their glyphs in the source tables are the Persephone and Vulcanus symbols used in that literature.

References

• E.O. Eshuis, Informatie Astrolab: the program's feature list, including the corrected Black Moon, Black Sun, Diamond, and "Persephone en Vulcanus volgens Carteret", computed with JPL and Swiss Ephemeris routines.
• Monique Leurink, About Diamond Astrology, which links to the astrolab.nl ephemeris.
• Cees J.A. Jansen, Over het Apogeum van de Maan en de Gecorrigeerde Zwarte Maan (2021). Shows that Bode's correction table is 12.3 × sin 2α and discusses the Duval & Font ephemerides.
• Cees J.A. Jansen, Vulcanus in een Dominante Leerdriehoek met Neptunus en Priapus: Vulcanus at about 33′ a year, in Gemini since about 1980, positions fixed by Carteret.
• George Bode, Zwarte Maan, Zwarte Zon, Drakenkop, Stichting Vulcanus, Amsterdam 2001 (correction table on p. 239).
• George Bode, De Nieuwe Planeten: Persephone en Vulkanus, als aanvulling op Uranus, Neptunus en Pluto, 1981.
• Max Duval & Jean-Marc Font, Tables du Nœud Lunaire, de Lilith et du Soleil Noir, Dervy-Livres, Paris 1988.
• Lune noire (astrologie), French Wikipedia, on the origin of the corrected Black Moon.
• Jean Meeus, Astronomical Algorithms, 2nd ed., 1998: mean longitude of Earth's perihelion (ch. 31) and of the lunar apogee (ch. 47).
• Swiss Ephemeris (Astrodienst), used through pyswisseph with the built-in Moshier ephemeris to recompute the Sun and mean apogee for every day.

Source: astrolab.nl Diamond Astrology Ephemeris.