Dynamic Astrocartography / Cyclocartography — Progressed Planetary Lines Over Your Lifetime

What dynamic astrocartography is

Standard astrocartography fixes one instant — your birth — and asks where on Earth each planet rose or culminated at that moment. Dynamic astrocartography (also called cyclocartography) asks the same question at a whole sequence of instants derived from your life: the secondary-progressed chart at age 5, at age 10, at age 15, all the way to your nineties. Each snapshot produces its own set of lines, and those lines drift as the progressed sky moves.

Secondary progressions use the 1-day-per-year convention: your chart at age 30 is cast for the sky 30 days after your birth date. That convention is a symbolic choice with centuries of practice behind it, not an astronomical one; the map inherits that convention. The output is a colour-coded timeline of planetary line positions — childhood-blue lines fading through midlife-gold into later-life-red, so you can visually scan where each planet's ASC or MC sat during each decade of your life.

How the moved lines are computed

At each age in your timeline we advance the birth instant by `age` days (secondary progression), place every planet from sub-arcsecond astronomy (VSOP87/ELP via astronomy-engine) at that progressed instant, and re-solve the astrocartography equations the same way the natal map does — invert the horizon equation for each latitude to find the longitude where the planet rises or culminates. Every age produces a fresh full line family; sampled at 5-year intervals from 0 to 90 that's nineteen snapshots per angle per planet.

Each snapshot is drawn as a polyline coloured by its age (childhood starts deep blue, midlife passes through gold, later years finish in warm red) with a light transparency so overlaid snapshots read as a time-lapse rather than a tangle. Antimeridian crossings are segmented cleanly so the map never draws a spurious horizontal streak. Only the ASC and MC families are shown by default — DESC and IC are available via the angle toggles but add clutter fast at nineteen snapshots per planet.

What you get

Once your birth data is entered:

• A world map with the progressed line family for each selected planet and angle, colour-coded by age from 0 to 90.
• Angle and planet toggles so you can isolate a single timeline (e.g. Venus ASC only) or a coherent subset (personal planets ASC only).
• A legend mapping the colour ramp back to specific decades — childhood / adolescence / midlife / later years.
• A short methodological note on the 1-day-per-year convention so a reader can see the symbolic choice behind the arithmetic.

Reading a moving map

The technique was formalised by the astrocartography community as a way to answer a question the fixed natal map cannot: does the Venus-ASC line that runs near Cairo at birth still run near Cairo when you're 42, or has it drifted west? Because the progressed Moon moves about 13° per progressed year (i.e. one degree of longitude per lunar year), fast-planet lines sweep hundreds of kilometres of ground across a lifetime, while slow-planet lines barely shift. That difference is the map's most informative pattern.

Discipline: dynamic astrocartography multiplies the amount of map by an order of magnitude, which makes cherry-picking easy. Practitioners generally ask one question at a time — 'where was my Jupiter-ASC line during my thirties' — rather than reading every snapshot. It's a timeline, not a horoscope; each polyline is one instant's line, and the visual story is in the drift.

A worked example, with real numbers

For a birth at 17:30 UTC on 1 January 2000 in London, the natal Sun's MC line sits at about 27°W longitude (Greenwich sidereal time at the instant, projected through the MC meridian). At age 30 the progressed instant is 31 January 2000 at 17:30 UTC; the progressed Sun has moved roughly 29° along the ecliptic and the MC meridian on the map drifts about 116° westward.

At age 60 the progressed instant is 1 March 2000; the Sun-MC line has swept another 116° west. That 116°-per-decade progression is characteristic of the Sun's secondary progression and illustrates why the personal-planet lines carry the most visible motion on this map.

The progressed Moon moves far faster: at roughly 13° of ecliptic longitude per progressed year, its ASC line completes a full global sweep every 6-7 years of lived time. Selecting Moon-ASC on the map makes the pattern obvious: the childhood-to-later-life colour ramp cycles through the world's longitudes repeatedly, and there is no single static Moon line.

What this tool does not claim

The 1-day-per-year progression convention is a symbolic choice with traditional justification, not an astronomical fact. The line geometry is exact for whatever instant you feed it; the mapping of that geometry onto lived years is the technique's interpretive frame. Relocation-effect claims (astrocartographic or cyclocartographic) have no controlled-evidence base.

Sampling at every 5-year age is a compromise between completeness and clutter: at 1-year resolution the map holds nine times as many polylines and stops being readable. Line solving near the poles is exact but solutions genuinely do not exist for some planets at high latitudes — line endings are data. With unknown birth time, the whole timeline anchors to an estimated noon instant. Calculations run entirely in your browser. Your birth data is never uploaded, never stored on a server, and never shared.

Cyclocartography vs solar-return map vs relocation

Cyclocartography is the smooth drift of the progressed sky's lines across a whole lifetime. A solar-return map does the same job annually: cast the chart when the transiting Sun re-crosses your natal Sun and draw that year's lines, giving one snapshot per year rather than a continuous timeline.

Relocation charts (see `/tools/relocation-chart`) ask a different question again — how do the houses of your natal chart shift in a specific city? Practitioners combine all three: natal map for the fixed structure, cyclo map for lifetime drift, solar-return map for the specific year you're asking about.

Our method in one line

Secondary-progressed instants at every 5-year age from 0 to 90; positions from sub-arcsecond astronomy (VSOP87/ELP via astronomy-engine); lines solved numerically at 4° latitude steps (bisection-refined); polylines drawn in equirectangular projection over Natural Earth 110m coastlines and coloured by age. Reviewed by Dr. Amara Osei, Astronomy Reviewer.