Secondary
Progressions

Secondary progressions count each day after birth as one year of life. The chart for your 30th year is the sky 30 days after you were born; the chart for your 60th, the sky 60 days after.

The result is a slow version of your birth chart. The progressed Moon moves as far in a year as the real Moon does in a day, between 11°45′ and 15°22′, so it changes sign every two years or so. The progressed Sun moves about a degree a year and changes sign two or three times in a lifetime. Mercury, Venus and Mars move between none and a few signs depending on their speed after your birth, and from Jupiter outward the planets barely move at all; a planet that was about to turn retrograde or direct when you were born may do so in your progressed chart.

Astrologers read the progressed chart against the birth chart: a progressed planet that reaches an aspect to a natal one, a progressed planet changing sign or direction, and the phase between the progressed Sun and Moon. Many treat these as slow inner changes and use transits, the planets' real positions, for outside events. This page explains exactly how the calculator works, walks through a full example for Barack Obama, and gives the tables behind the questions people ask most: when the progressed Sun changes sign, how long the progressed Moon stays in each sign, and when progressed New and Full Moons fall.

Your birth details go to the site's API, which casts the natal chart from the Swiss Ephemeris (the methodology page describes the setup) and then works through these steps:

1. Age. The date you choose is read as 00:00 on that day in your birth time zone. The time from your birth to that moment, in days, divided by 365.2422 (the mean tropical year) is your age in years, with its fraction.
2. Progressed moment. That many days are added to your birth moment. For Barack Obama's 60th birthday the age is 59.9991 years, so the planets are cast for October 4, 1961 at 05:22:39 UT, to the second.
3. Planets. The Sun, Moon and planets are the Swiss Ephemeris positions at that moment, tropical zodiac, with their speeds, so the calculator knows which ones are retrograde.
4. Angles. The sidereal time of your birth (the right ascension of the Midheaven) is advanced 0°59′08″ for every year of life, and the Ascendant, Midheaven and house cusps are worked out from it at your birth latitude. Houses are Whole Sign, as on the site's other calculators.
5. Aspects. The ten progressed planets, the Ascendant and the Midheaven are compared with the same twelve points in the birth chart for the conjunction, sextile, square, trine, opposition, semi-square, sesquiquadrate and quincunx, within 1°. Jupiter to Pluto are not compared with their own birth positions: even Jupiter moves less than 30° in a century of progression, so the only contact they could make with themselves is the conjunction they start in. Each aspect gets the date it is exact, found by searching five years either side.
6. Timeline. From birth to age 100 the API lists every progressed sign change of the ten planets, every progressed New Moon, First Quarter, Full Moon and Last Quarter, and every progressed station. Each ephemeris moment is converted back to a date in your life: one day of ephemeris time is 365.2422 days of life.

Why the angles are not taken from a chart for the progressed moment

A chart cast for the progressed moment gets the planets right, but its angles turn once around the zodiac for each day of ephemeris time, that is, once a year of life. Half a year after his 60th birthday, a chart for Obama's progressed moment would put the Midheaven at 24°04′ Cancer; the progressed Midheaven by the rule above is 24°23′ Capricorn, almost exactly opposite. On each birthday at the birth time the two agree, and that birthday chart is what casting the progressed day by hand gives. Between birthdays the calculator keeps the angles moving at the same steady rate, about a degree a year, instead of letting them spin.

The progressed Moon's house is counted in your natal Whole Sign houses, as it is usually read: the progressed Moon passing through your natal 7th house, for example.

Obama's birth certificate records his birth in Honolulu at 7:24 PM (UTC−10:00) on August 4, 1961, which is 05:24 UT on August 5, 1961. On his 60th birthday, August 4, 2021, read as 00:00 Honolulu time, he was 59.9991 years old, so his progressed chart is the sky over Honolulu 59.9991 days after his birth: October 4, 1961, 05:22:39 UT. The example script recomputes every position here with pyswisseph, bypassing the API, and stops if any of them differs.

The Sun has moved 58°11′ in 60 years, from 12°32′ Leo to 10°44′ Libra: slightly less than a degree a year, because the Sun moves more slowly in August and September than around January. It entered Virgo on October 3, 1979 (age 18.2) and Libra on August 24, 2010 (age 49.1), and it reaches Scorpio on January 9, 2041, at 79.4. That 58°11′ is also his solar arc at 60, the figure the Solar Arc calculator adds to every point.

The Moon started at 3°21′ Gemini and now moves about 11°47′ a year. It has been around the zodiac twice, returning to its birth degree on November 14, 1988 (age 27.3) and March 22, 2016 (age 54.6), and at 60 it is at 9°41′ Leo: it entered Leo on October 8, 2020 and moves into Virgo on April 25, 2023. His Ascendant is in Aquarius, so the progressed Moon is in his 7th Whole Sign house.

Jupiter and Saturn were both retrograde when he was born. Progressed Jupiter backed out of Aquarius into Capricorn on September 26, 1968 (age 7.1) and turned direct on January 4, 2011 (age 49.4) at 27°19′ Capricorn; it will not be back in Aquarius until age 90.9. Progressed Saturn turned direct on March 7, 2015 (age 53.6) at 23°14′ Capricorn. Progressed Mercury, at 5°40′ Scorpio now, is slowing toward a retrograde station on April 23, 2028 at 8°01′ Scorpio, and turns direct again on February 11, 2049. Progressed Mars entered Scorpio on March 15, 2019.

Aspects within 1° on the birthday are below, tightest first. The exact dates show which are still building. The tightest, progressed Uranus square his natal Midheaven, is exact on December 10, 2022. Where no date is given, the progressed planet moves so slowly that it stays within the orb for more than five years either way.

The progressed Sun moves as far each year of life as the real Sun moves in a day, between 0°57′ and 1°01′, so it changes sign after roughly as many years as it has degrees left in your birth sign. Someone born with the Sun at 25° of a sign sees it move on at about 5; someone born at 2° waits until their late twenties. After that first change it spends about three decades in each sign, a little longer in the signs the Sun crosses around July than in those it crosses around January, because the Earth is farthest from the Sun in early July and moves slowest then.

The table gives the number of days the Sun spends in each sign, averaged over the years 2001 to 2020 from the Swiss Ephemeris, which is the number of years the progressed Sun spends there. The longest stay is Cancer at 31.45 years; the shortest, Capricorn at 29.44.

The calculator gives your own dates: the day your progressed Sun entered its current sign, the day it moves on, and every progressed Sun sign change to age 100. How each sign phase is usually read:

The progressed Moon is the fastest moving point in the progressed chart and the one astrologers time most by. Its pace depends on the real Moon's speed in the weeks after your birth, which varies with its distance from Earth. Measured from every lunar sign change between 1950 and 2050, a sign takes the progressed Moon 1.95 to 2.55 years, 2.28 on average, and a full circle back to its birth degree takes 27.22 to 27.47 years. So most people have a progressed Moon return in their late twenties and another in their mid-fifties.

Obama's second circuit, from his first progressed Moon return to his early sixties, shows the uneven pace: Pisces took 2.00 years and Leo 2.54.

Because the progressed Moon moves much faster than the progressed Sun, it laps it, and the angle between them runs through the same phases as the Moon in the sky: New Moon when the two meet, Full Moon when they are opposite. One lap takes as many years as a lunar month takes days, 29.28 to 29.83 (29.53 on average, from 1,236 lunations between 1950 and 2050). Dane Rudhyar divided the cycle into eight phases of 45° each, New, Crescent, First Quarter, Gibbous, Full, Disseminating, Last Quarter and Balsamic, and read the progressed cycle as a 30-year rhythm of starting, building, culminating and clearing away.

Obama was born 291° into the cycle, in the Last Quarter phase (270° to 315°), with the Moon 69° short of New. His progressed Moon caught up with his progressed Sun for the first time on October 23, 1967, at age 6.2, in Leo. At 60 the angle is 298°, Last Quarter again, one full cycle later; the next progressed New Moon falls on February 25, 2027, in Libra. The calculator shows the same for your chart: the current phase, the last principal phase and the next one.

The planets in a progressed chart are not in dispute; the angles are. There is no sky to look at for a progressed Ascendant, so each method is a rule for moving the birth Midheaven forward, after which the Ascendant is the one that rises with it at the birth latitude. Four rules are in common use, and the calculator returns all four for your chart:

• Progressed sidereal time (Naibod rate in right ascension), used by this calculator: the sidereal time of birth plus 0°59′08″ a year. Astrodienst's help pages describe the same rule for its progressed charts: the years of life times the Sun's mean daily motion, 0.98564733°, added to the sidereal time of birth.
• Solar arc in right ascension: the birth Midheaven moved in right ascension by as much as the progressed Sun has moved in right ascension.
• Solar arc in longitude: the birth Midheaven plus the solar arc in zodiacal longitude, the same arc solar arc directions use. Astrodienst offers this as “MC from solar arc” and attributes it to the Solar Fire program.
• Naibod rate in longitude: the birth Midheaven plus 0°59′08″ of longitude a year.

For Obama at 60 the four Midheavens span 8°07′ and the four Ascendants 10°26′. His progressed Midheaven moves about 0°55′ a year at this point and his Ascendant about 1°11′, so the choice of method can move the date of a Midheaven contact by up to about 9 years. The square of his progressed Ascendant to natal Mercury in the table above, exact on January 18, 2021 by this calculator's method, would be years earlier or later by another. The two solar arc methods differ from the Naibod ones because his progressed Sun moved more slowly than average, and the right ascension methods differ from the longitude ones because a degree of the equator and a degree of the zodiac are not the same size near the solstice points.

None of the four is more correct astronomically; they are conventions. The calculator uses the progressed sidereal time because it reproduces the traditional chart for the progressed day at the birth time on every birthday and moves smoothly in between, and because Astrodienst's charts use it by default. If you work with another method, read your angles from that row of the result.

• Placidus de Titis, Tabulae primi mobilis (1657), translated by John Cooper as Primum Mobile (London, 1814). Placidus called the day-for-a-year motions “secondary directions” to set them apart from primary directions. He presented them as Ptolemy's, but Ptolemy's timing method in Tetrabiblos Book III is a primary direction, with a degree of the equator for each year. A count of days after birth standing for years of age already appears in Vettius Valens's Anthology, Book IX (2nd century).
• Alan Leo, The Progressed Horoscope (London, 1906), a textbook built around the day-for-a-year method.
• Dane Rudhyar, The Lunation Cycle (1967), for the eight lunation phases and the progressed lunation cycle.
• Astrodienst's chart help pages, for its progressed-angle rule and the value 0.98564733° for the Sun's mean daily motion.
• The Swiss Ephemeris (Astrodienst) for every position, and its swe_houses_armc function for angles and cusps from a sidereal time.

The calculator needs an accurate birth time: the Earth turns a degree every four minutes, so a four-minute error moves the progressed angles by about a degree, a year of timing, and a two-hour error moves the progressed Moon by up to 1°16′, about a month. Positions are tropical. The lunar nodes, Chiron and the asteroids are left out of the progressed aspects. The full-precision ephemeris files cover the years 1800 to 2399.