Astrocartography: your map of places in PDF

What the lines actually are

At the minute you were born, every planet stood at one degree of the zodiac, and that degree was crossing the sky above the place of birth. Because the Earth turns, any given degree rises in the east somewhere, sets in the west somewhere, crosses the local meridian somewhere, and crosses the opposite meridian somewhere else. Astrocartography takes that moment and asks a narrow question: where on the globe was this planet angular? Four answers come back for each body, and each answer is a curve.

The four are named for the angle the planet made with the local horizon and meridian: the Midheaven line (MC), the Imum Coeli line (IC), the Ascendant line (ASC) and the Descendant line (DSC). The usual set of ten bodies, Sun through Pluto, produces about forty lines, all fixed to the same moment.

The MC and IC lines run close to north and south. Both mark places where the planet sat on the local meridian, which is a line of longitude. Draw it on a globe and it runs from pole to pole. Flattened onto a rectangular map it appears nearly vertical, bending only through the projection and the planet's own drift across the day.

The ASC and DSC lines behave differently. They trace the places where the planet's degree was exactly on the eastern or western horizon. That set of places is a great circle tilted against the meridians, so on a map it sweeps across the page in a long curve. Near the equator the curve is relatively straight. Toward the poles it bends hard, and in some latitudes it can end up thousands of kilometres from the MC line of the same planet. A city can therefore sit close to a planet's MC line and very far from its ASC line. The two are not interchangeable and do not run parallel.

How close is close

A line on a map has no width, and a city has a location. Deciding whether the city counts as being on the line is a judgement about distance, and the judgement belongs to the reader, not to the map. The useful move is to fix a distance before looking, then apply it consistently. A workable convention is a band of roughly 150 to 300 km around each line. It is a convention, not a rule. Choose a narrower band and fewer places qualify. Choose a wider one and half a country starts to look relevant.

One degree of longitude measures about 111 km at the equator. The same degree shrinks as you move toward the poles, because lines of longitude converge. At 40 degrees of latitude, north or south, a degree of longitude is about 85 km. A fair approximation is 111 km multiplied by the cosine of the latitude.

If a city sits half a degree of longitude from an MC line at the latitude of Madrid or New York, it is about 42 km away and plainly inside a 150 km band. The same half degree near the Arctic Circle covers far less ground, so lines bunch together and almost everything looks close. Distance to an ASC or DSC line is harder to estimate by eye, because the curve runs diagonally. Measure the shortest distance to the curve rather than the distance along a parallel.

Two readers can disagree with neither being wrong: one treats a 400 km separation as close enough, the other as off the line. The threshold is worth stating before a reading begins. The glossary defines the terms used here, and the natal chart is where the underlying positions come from.

What it cannot tell you

• The lines do not change. They are fixed to the birth moment and the geometry of the Earth. Moving to a line does not redraw it, and a place does not become a different place because you arrived with a map in hand.
• The map does not decide for you. It marks where a planet was angular, which is emphasis, not outcome. Two people born minutes apart can stand on the same line and live entirely different lives there.
• There are no lucky cities. A line does not make a place good, safe, prosperous or suitable in general. It records one astronomical fact about one moment.
• It does not replace a decision. Work, rent, family, health, papers, money: the map is one input among several, and the other inputs usually weigh more.

Common questions

How exact does my birth time need to be?

The lines are drawn from planetary positions at the moment of birth, so time matters. The Earth turns fifteen degrees of longitude per hour, which is a quarter of a degree per minute. A four minute error in a recorded time can move an MC line by about a degree of longitude, roughly 111 km at the equator. A birth certificate is a better starting point than a family recollection.

Do I have to live on a line for it to count?

No. A visit, a long stay and a permanent move are different things, and the map does not rank them. What changes is the time spent inside the band you chose, which is a fact about your itinerary.

What is the difference between this map and a relocated chart?

A relocated chart takes the same birth moment and calculates it for a different place, producing a full set of houses for that location. The map shows many places at once and is useful for narrowing a list of candidates. They answer different questions, and a sample reading shows the written format.

Which line should I look at first?

Start from the question you are actually asking. A map read without a question tends to produce a list of cities with no reason to prefer one. Read the two or three lines that touch places already on your list before adding new places to it.