Firdaria Calculator — Your Life in Planetary Chapters

What a firdar period is

A firdar is a stretch of years ruled by one planet. The word comes from the Arabic al-firdariyyat, and the technique was codified in ninth-century Baghdad by Abu Ma'shar, who lived from 787 to 886. It reached the Latin West through translation and was used by Bonatti and later by William Lilly.

There are seven firdars, one for each classical planet. They run in the descending Chaldean order, but the order is rotated so that it opens on the light that rules your birth. A day birth starts with the Sun. A night birth starts with the Moon.

The chapters are not equal. The Sun rules ten years, Venus eight, Mercury thirteen, the Moon nine, Saturn eleven, Jupiter twelve and Mars seven. Added together that is a seventy-year cycle, after which the sequence begins again.

Each chapter divides into seven sub-periods of one-seventh its length. The first sub-period belongs to the chapter lord itself, and the remaining six follow the same sect order. So a Saturn chapter contains a little Saturn, then a little Jupiter, then a little Mars, and so on.

How the timeline is built

The only natal fact firdaria needs is sect. That is whether the Sun stood above or below the horizon at your birth, which is why a birth time matters here and an approximate time is not enough.

Once sect is fixed, the sequence is decided. A day birth runs Sun, Venus, Mercury, Moon, Saturn, Jupiter, Mars. A night birth runs the same circle starting one step away: Moon, Saturn, Jupiter, Mars, Sun, Venus, Mercury.

Ages are counted from birth, not from conception or from your zero-point lunation. The first chapter begins at age zero and the last one closes the cycle at exactly seventy. Our probe asserts that the seven chapters tile the cycle with no gap and no overlap.

Sub-periods fall out of simple division. Eleven years over seven is about 1.57 years, so a Saturn chapter breaks into slices of that size. Thirteen years of Mercury gives slices near 1.86 years, and seven years of Mars gives exactly one year each.

Firdaria beside the other time-lords

Firdaria is one of several clocks in the traditional tradition, and it is worth knowing which one you are looking at. Annual profection moves one sign per year and names a lord for a single year. Firdaria moves in decades and names a lord for a whole chapter.

Zodiacal releasing is finer and stranger. It counts from the Lot of Fortune or Spirit through the zodiac, doubling through signs, so its periods can be a few months or a few decades. Firdaria is steadier and easier to hold in your head.

Alcocoden and the Arabic parts of age give a different answer again, because they weight a single lord by its dignity and derive years from that score. Firdaria ignores dignity in the timing itself. The planets keep their fixed lengths no matter how weak they sit.

Dignity still matters, but it enters at the reading stage. The chapter lord arrives with its natal sign, house and aspects attached, and that is what tells you whether the chapter brings the good of its planet or the hard side of it.

What the report returns

Once you cast, the calculator prints:

• Your sect, and the exact order of lords your birth opens on.
• The seven chapters as age ranges, with the current one marked.
• The active chapter and sub-period for any age you type in.
• The natal sign and whole-sign house of every chapter lord.
• All seven sub-periods of the chapter you select, with their own age ranges.

A worked example: the London midnight chart

Take the fixed test chart used across this site: London, 17:30 UT on 1 January 2000, latitude 51.5074, longitude minus 0.1278. The Sun is below the horizon, so this is a nocturnal birth and the cycle opens on the Moon.

The night order gives Moon first for nine years, from birth to age nine. Saturn follows for eleven years, from nine to twenty. Jupiter rules twelve years, from twenty to thirty-two. Mars takes seven, from thirty-two to thirty-nine.

Then the Sun arrives for ten years, from thirty-nine to forty-nine, and Venus for eight, from forty-nine to fifty-seven. Mercury closes the cycle with thirteen years, from fifty-seven to seventy. At seventy the count restarts on the Moon.

Each lord brings its own natal seat. Here the Moon sits in Scorpio in the fifth house, Saturn in Taurus in the eleventh, Jupiter in Aries in the tenth and Mars in Aquarius in the eighth. The Sun and Mercury are both in Capricorn in the seventh, and Venus is in Sagittarius in the sixth.

Open the Saturn chapter and the seven sub-periods appear at 9.00, 10.57, 12.14, 13.71, 15.29, 16.86 and 18.43, each running to the next. Saturn, then Jupiter, then Mars, then Sun, then Venus, then Mercury, then Moon. Those boundaries match the printed nocturnal table in Robert Zoller's essay on planetary periods exactly.

How to read a chapter

Start from the lord's nature, then narrow it with its natal condition. A Jupiter chapter carries growth, teaching, travel and excess in general. Whether yours does depends on where Jupiter sits, what sign it is in and what aspects it receives.

Next, read the house. The chapter plays out loudest in the area the lord occupies. A Mars chapter with Mars in the eighth house will not feel like a Mars chapter with Mars in the third, even though the length and the planet are identical.

Then look at the sub-period as a modifier on the chapter, never as a replacement. A Venus sub-period inside that Saturn chapter is warmth and connection running through a period of discipline and building. The chapter keeps its shape; the sub-period tints it.

Finally, layer the clocks. Traditional practice stacks firdaria with profection, solar return and transits. When the chapter lord, the lord of the year and an active transit all point at one planet, the tradition says the theme is genuinely loaded.

What this tool does not claim

The variant we do not compute is the node-appended cycle. Several authorities, including Zoller and the guides that publish the same table, add three years for the North Node and two for the South Node, making a seventy-five-year cycle instead of seventy. Those node periods are normally left un-subdivided.

We ship the pure seven-planet cycle. It is the version on which the surviving sources agree most cleanly, and it keeps the arithmetic honest: seven chapters, seven sub-periods each, seventy years, then repeat. If you work with a seventy-five-year table, the two systems will drift apart after the Mars chapter.

Firdaria also assumes a birth time good enough to settle sect. If the Sun sat near the horizon at your birth, the whole order can flip and every date moves with it. Our birth-time rectification tool exists for exactly that case.

And no chapter is inherently lucky or unlucky. Length and order are fixed arithmetic; the quality of a period depends on the state of that planet in your own chart. Nothing here predicts events, sets dates for anything, or replaces judgment.

Our method in one line

Positions come from sub-arcsecond astronomy (VSOP87/ELP via astronomy-engine), cast in Porphyry quadrant houses (whole-sign available on every chart), and the chapter table is the classical firdar-years set, asserted against three independent published guides.

Every age range in the worked example above is reproduced by the Batch E-1 engine probes on this fixed test chart, including the Saturn sub-period boundaries to two decimal places. Reviewed by Dr. Amara Osei, Astronomy Reviewer.