One Day, One Year

Secondary Progression

In the classical tradition, one day is counted as one year. This tool symbolically progresses your birth chart to the target date you choose; it shows the progressed planets, the Placidus angles, the progressed Moon phase and a timeline of the coming years.

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Birth & Target Details

Birth
Target
The natal and progressed charts in three zodiacs: tropical signs, sidereal (Lahiri ayanamsa) and draconic (North Node at 0° Aries) placements.

Don't know or aren't sure of your birth time? The rising sign and house placements are very sensitive to the time; you can clarify your time with an event-based rectification (birth time determination) consultation.

Inner ring: Natal Outer ring: Progressed

Progressed Chart Summary

Age (at target)—
Progressed date (ephemeris)—
Angle method—
Progressed ASC—
Progressed MC—
Progressed Sun—
Progressed Moon—

Progressed Points (Placidus houses)

PointPositionHouse

Progressed → Natal Aspects (orb ≤ 1°)

AspectOrbDirection
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Part I

Progressed Moon Report

The progressed Moon is the fastest-moving point in secondary progression: it crosses a sign in about 2.5 years and the whole zodiac (the progressed lunation cycle) in about 29.5 years. It is therefore a classical timer for reading the month-to-month tempo of life.

Calculate the progression above first.

Part II

Progressed Sun

The progressed Sun moves about 1° per year; it completes a sign in roughly 30 years. Its sign change is regarded in the classical tradition as a rare and important threshold marking a long chapter of life.

Calculate the progression above first.

Part III

The Timeline

From the target date forward, the progressed Moon's sign ingresses (~2.5 years/sign) and the conjunction, square, trine and opposition perfections the progressed Moon makes to natal planets are listed chronologically. Dates are approximate.

Calculate the progression above first.

About This Tool

The "One Day, One Year" Measure

Secondary progression (secondary direction) is a symbolic timing method that maps each calendar day after birth to one year of life. For a 30-year-old, the sky 30 days after birth is calculated; this progressed chart is compared with the natal chart to read the quality of the period.

The measure is ancient in origin. Ptolemy speaks of progressing the lights in the Tetrabiblos; the textual basis of the "one day, one year" principle is traditionally traced to Numbers 14:34 and Ezekiel 4:6 in the Hebrew Bible. As a technical doctrine, the form of "secondary direction" was given by Placidus de Titis in the 17th century; this is why secondary progression is associated with the Placidus house system.

"The path the Sun takes in a day corresponds to a year of life." The traditional measure was systematized as the secondary direction doctrine in Placidus de Titis's Primum Mobile (17th c.). Ptolemy · Placidus de Titis

Three Methods for Progressing the Angles

1. Daily motion (true), default. The MC and ASC are computed directly from the true local sidereal time of the progressed moment. This is the most natural and astronomically most consistent method.

2. Naibod. The RAMC is advanced by the Sun's mean daily motion (0.9856°) per year of age; the angles are found from this new RAMC. The planets remain at their secondary progression positions.

3. Solar Arc (solar arc). The arc the progressed Sun has travelled from the natal Sun is computed and all points (including the planets) are advanced by this equal arc. In this method the angles move by the same arc as the planets, so all aspects are preserved.

This tool is for study and preliminary work; it does not replace a classical reading. It is a symbolic clock: the sky does not actually move at this speed. Dates are approximate; for precise angle and progressed Moon positions an accurate and, if possible, rectified birth time is required. Honest-use note
One-on-One Reading

Let's Read Your Progressed Chart Together

For a classical timing consultation that considers secondary progression, transits and profection together, you can reach out to Şira.

  • ✦ Progressed Moon and Sun timing
  • ✦ Classical technical coherence
  • ✦ Personalized period analysis
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For those who want to learn timing techniques systematically Education →

Frequently Asked Questions

What is secondary progression?

Secondary progression (secondary direction) is a classical timing technique that counts each day after birth as one year of life. This is called the "one day for one year" (dies pro anno) measure. For a 30-year-old, for example, the sky positions 30 days after birth are calculated and compared with the natal chart. The measure is ancient in origin; Ptolemy touches on it in the Tetrabiblos, and Numbers 14:34 and Ezekiel 4:6 in the Hebrew Bible are cited for the "one day for one year" principle.

Where does the "one day for one year" measure come from?

The measure rests on the idea that the path the Sun travels in a day corresponds to a year of life. In late antiquity Ptolemy speaks of progressing the lights (Sun and Moon). As a technical doctrine it was systematized in the form of "secondary direction" by Placidus de Titis in the 17th century. This is why the Placidus house system is most often used in progressing the angles.

What is the difference between daily motion, Naibod and Solar Arc for the angles (MC/ASC)?

The three methods progress the angles differently. Daily motion (true): the MC/ASC are computed from the true sidereal time of the progressed moment; this is the most natural method and the default here. Naibod: the RAMC is advanced by the Sun's mean daily motion (0.9856°) per year of age. Solar Arc: all points (including the planets) are advanced equally by the arc the progressed Sun has travelled from the natal Sun; in this method the angles move by the same arc as the planets.

Why is the progressed Moon so important?

The progressed Moon is the fastest-moving progressed point; it crosses a sign in about 2.5 years and completes the whole zodiac (the progressed lunation cycle) in about 29.5 years. This speed makes it a classical timer for reading the month-to-month tempo of life. The aspects the progressed Moon makes to natal planets and its sign/house changes are the main markers of a period's quality.

How is the progressed Moon phase (lunation cycle) read?

The angle between the progressed Moon and the progressed Sun forms an eight-phase cycle: New Moon (0-45°), Crescent (45-90°), First Quarter (90-135°), Gibbous (135-180°), Full Moon (180-225°), Disseminating (225-270°), Last Quarter (270-315°) and Balsamic (315-360°). This roughly 29.5-year cycle marks a personal rhythm of development, harvest and release, and relates to the natal Moon phase at birth.

Is a birth time needed for secondary progression?

The minute of the birth time is not critical for the progressed longitudes of the planets; however the progressed MC, ASC and house cusps depend directly on the birth time. Even a few minutes of uncertainty can shift the progressed angles and especially the house position of the fast progressed Moon. For precise angle progression an accurate and, if possible, rectified birth time is recommended.

What is the difference between a progressed chart and a transit?

Transits are the contact of the real-time sky with the natal chart; they point to outer, observable events. Secondary progression is a symbolic clock: the sky does not actually move at that speed, the days after birth are mapped to years. In the classical tradition progression shows inner/developmental timing while a transit shows the triggering outer event; read together, the timing is strengthened.

Which house system and calculation does this tool use?

The tool uses the Placidus house system that secondary progression is historically associated with; the cusps are computed by the iterative semi-arc method. Planet longitudes are found with an astronomical ephemeris engine (astronomy-engine), tropical and of-date. The aspect orb is kept narrow (≤1°) because progression is slow.

What happens when the progressed Sun changes sign?

The progressed Sun changes sign roughly every 30 years (~1° per year). This rare event is regarded in the classical tradition as an important threshold marking a long chapter of life; it is read as a period in which a person's basic orientation shifts in nature. The tool computes the approximate date of the next sign change.

A Systematic Approach to Timing

Secondary progression is only one part of the classical timing techniques. For a holistic reading of time, alongside profection, solar return, primary directions and transits, you can explore the courses.

Explore the Courses