Midheaven (MC) – Career, Public Image
Immum Coeli (IC) – Home, Family Roots
Ascendant (ASC) – Personality, First Impressions
Descendant (DSC) – Relationships, Partnerships
Sun Line – Vitality, Self-Expression
Moon Line – Emotions, Domesticity
Mercury Line – Communication, Travel
Venus Line – Love, Relationships, Finances
Mars Line – Energy, Action, Conflict
Jupiter Line – Growth, Luck, Opportunity
Saturn Line – Structure, Discipline, Challenges
Uranus Line – Innovation, Unpredictability
Neptune Line – Spirituality, Illusion, Dreams
Pluto Line – Transformation, Power, Intensity
Understanding Astrocartography Lines
Astrocartography, a branch of astrology, maps the influence of planetary energies across the globe. It uses your unique birth chart (natal chart) – the precise time, date, and location of your birth – to draw lines on a world map. These lines represent locations where specific planets were angular (rising, setting, at their zenith, or nadir) at the moment of your birth. Traveling or living along these lines is believed to accentuate the energies of the planet associated with that line.
The Underlying Calculation Principles
The calculation of astrocartography lines involves determining the geographic coordinates (latitude and longitude) of locations where a specific planet was in an angular position relative to the horizon and meridian at your birth time. The core of the calculation relies on:
Sidereal Time: This is the time measured by the stars, essential for accurate celestial positioning.
Planetary Positions: Determining the exact ecliptic longitude and latitude of each planet at the moment of birth, relative to the Earth's equator and prime meridian.
Local Horizon and Meridian: At any given point on Earth, the horizon and meridian change based on latitude and longitude. The Local Apparent Sidereal Time (LAST) links these to the Sidereal Time at Greenwich.
Angular Positions: Planets are considered "angular" when they are on the horizon (Rising/Setting) or on the meridian (Midheaven/Nadir).
The lines on an astrocartography map represent areas where a planet is crossing one of these four key angular points:
Ascendant (ASC) Line: Represents where the planet was rising on the eastern horizon. This line impacts your personality, how you present yourself, and your immediate environment.
Descendant (DSC) Line: Represents where the planet was setting on the western horizon. This line relates to partnerships, relationships, and one-on-one interactions.
Midheaven (MC) Line: Represents where the planet was at its highest point in the sky (culminating). This line influences career, public image, ambition, and life direction.
Immum Coeli (IC) Line: Represents where the planet was at its lowest point in the sky (nadir). This line relates to home, family, roots, and inner security.
Additionally, lines can be drawn for the planets themselves, indicating locations where that planet's energy is particularly strong and accessible, often influencing the areas of life governed by that planet (e.g., Venus lines for love and finances, Mars lines for energy and action).
How This Calculator Works (Simplified)
This calculator provides a simplified approximation. It calculates the difference in longitude between your birth location and the calculated location of the angular planet at your birth. The formulas used are approximations derived from spherical trigonometry and astronomical calculations. They aim to pinpoint locations on Earth that align with the angular positions of planets relative to your birth chart's astrological house system cusp definitions.
For a specific line (e.g., Sun-MC), the calculator determines the longitude where the Sun was at the Midheaven position at your birth time. It then calculates the difference between this longitude and your birth longitude. This difference, combined with your birth latitude, gives an approximate longitude for the line passing through your location. The exact mathematical conversion from sidereal time, planetary ephemerides, and spherical coordinates to geographic latitude and longitude on a specific angular degree is complex and typically handled by specialized astrological software. This calculator offers a conceptual estimation.
Simplified Calculation Logic (Conceptual):
The core idea is to find a geographic longitude (Lon_Line) such that when combined with the local latitude (Lat_Birth) and the Local Apparent Sidereal Time (LAST) at birth, a specific planet (Planet_RA/Dec) falls on the desired angular house cusp (e.g., MC, ASC).
The relationship between Sidereal Time (ST), Right Ascension (RA), Declination (Dec), Latitude (Lat), and Longitude (Lon) for an angular position can be approximated by equations like:
MC/IC lines:ST = RA ± arccos(tan(Dec) * tan(Lat)) (where ST is Local Apparent Sidereal Time, Lon_Line is derived from ST)
ASC/DSC lines:ST = RA ± arccos(-tan(Dec) * sin(Lat) / cos(Lat)) (where ST is Local Apparent Sidereal Time, Lon_Line is derived from ST)
This calculator's output is a conceptual representation of where the specific planet was located angularly relative to your birth location. It does not generate a full astrocartography map but can give an indication of the longitude where the chosen planet's line *intersects* your current location's latitude.
How to Use This Calculator
Enter your Birth Latitude and Birth Longitude in decimal degrees (e.g., 40.7128 for New York City, -74.0060 for New York City).
Enter your Current Location Latitude and Current Location Longitude in decimal degrees.
Select the Line Type you wish to analyze (e.g., Sun Line, Venus Line, MC Line).
Click "Calculate Line Intersection".
The result will indicate if the chosen line passes through your current latitude and provides an approximate longitude for that intersection based on the simplified calculation. This is a conceptual tool to understand the principles, not a replacement for professional astrological software or consultation.
// Helper function to calculate degrees, minutes, seconds from decimal degrees
function formatDegrees(decimalDegrees) {
var absoluteDegrees = Math.abs(decimalDegrees);
var degrees = Math.floor(absoluteDegrees);
var minutes = Math.floor((absoluteDegrees – degrees) * 60);
var seconds = Math.floor(((absoluteDegrees – degrees) * 60 – minutes) * 60);
var direction = decimalDegrees >= 0 ? (degrees === Math.abs(decimalDegrees) ? 'N/E' : 'N/E') : (degrees === Math.abs(decimalDegrees) ? 'S/W' : 'S/W'); // Simplified, needs context for N/S vs E/W
// Return a string indicating direction based on common convention
if (decimalDegrees >= 0) direction = "North/East"; else direction = "South/West";
return degrees + "° " + minutes + "' " + seconds + "\" " + direction;
}
// Basic approximation for Mean Sidereal Time (GMST) in hours
// Accurate calculations require Julian Day and more complex formulas
function getApproximateGMST(year, month, day, hourUTC) {
// Simplified approximation for days since J2000.0
var daysSinceJ2000 = (new Date(Date.UTC(year, month – 1, day, hourUTC, 0, 0)) – new Date(Date.UTC(2000, 0, 1, 0, 0, 0))) / (1000 * 60 * 60 * 24);
var approxGMST = 280.46061837 + 360.98564736629 * daysSinceJ2000 + 0.000387933 * Math.pow((daysSinceJ2000 / 36525), 2) – Math.pow((daysSinceJ2000 / 36525), 3) / 38710000;
return (approxGMST / 15) % 24; // Convert degrees to hours
}
// Approximate position of planets (using simplified ephemeris data – NOT accurate)
// These are rough average positions for illustration and NOT precise astrological values.
// Real calculations use detailed astronomical data (ephemerides).
var planetPositionsApprox = {
Sun: { longitude: 0, latitude: 0 }, // Example: Assume Sun at 0 Aries for simplicity in this demo
Moon: { longitude: 30, latitude: 5 }, // Example: Moon at 0 Taurus
Mercury: { longitude: 45, latitude: 2 },
Venus: { longitude: 60, latitude: 1 },
Mars: { longitude: 90, latitude: 0 },
Jupiter: { longitude: 120, latitude: -1 },
Saturn: { longitude: 150, latitude: -2 },
Uranus: { longitude: 180, latitude: -3 },
Neptune: { longitude: 210, latitude: -4 },
Pluto: { longitude: 240, latitude: -5 }
};
// Function to calculate Local Sidereal Time (LST)
function calculateLST(gmst, longitude) {
var lst = gmst + longitude / 15; // Convert longitude degrees to hours
return lst < 0 ? lst + 24 : lst % 24;
}
// Very simplified calculation for astrocartography lines
// This is a conceptual approximation and not precise astrological calculation software.
// It aims to show the *idea* of where a line might intersect a latitude.
function calculateAstrocartography() {
var birthLat = parseFloat(document.getElementById("birthLatitude").value);
var birthLon = parseFloat(document.getElementById("birthLongitude").value);
var currentLat = parseFloat(document.getElementById("currentLatitude").value);
var currentLon = parseFloat(document.getElementById("currentLongitude").value); // Not directly used for line calculation, but for context
var calculationType = document.getElementById("calculationType").value;
var resultDiv = document.getElementById("result");
resultDiv.innerHTML = ""; // Clear previous results
// Basic input validation
if (isNaN(birthLat) || isNaN(birthLon) || isNaN(currentLat) || isNaN(currentLon)) {
resultDiv.innerHTML = "Please enter valid numerical values for all coordinates.";
return;
}
if (birthLat 90 || currentLat 90) {
resultDiv.innerHTML = "Latitude must be between -90 and 90 degrees.";
return;
}
if (birthLon 180 || currentLon 180) {
resultDiv.innerHTML = "Longitude must be between -180 and 180 degrees.";
return;
}
// — Simplified Calculation —
// This simulation uses a placeholder for sidereal time calculation and planet positions.
// Real astrocartography requires precise ephemerides and astronomical algorithms.
// Placeholder: Use current date for a rough sidereal time estimate.
// A real calculation would use the *birth date and time*.
var now = new Date();
var approxGMST = getApproximateGMST(now.getUTCFullYear(), now.getUTCMonth() + 1, now.getUTCDate(), now.getUTCHours());
var lstAtBirthLocation = calculateLST(approxGMST, birthLon);
var planetInfo = {};
var eclipticLon = 0; // Ecliptic longitude of the planet
var eclipticLat = 0; // Ecliptic latitude of the planet
// Determine the target planet and its approximate ecliptic longitude
var targetPlanetName = "";
if (calculationType === "MC") {
targetPlanetName = "MC"; // MC is an angular point, not a planet itself
// For MC/IC, we need to calculate the MC degree based on LST and Latitude
// This is a major simplification. Accurate MC calculation depends on obliquity of the ecliptic.
// Approx MC Degree calculation:
var obliquity = 23.44; // Approx axial tilt of Earth
var mcDegreeApprox = (lstAtBirthLocation * 15) + (birthLon); // Approximation
// This needs to be converted to ecliptic longitude context
eclipticLon = (mcDegreeApprox + 180) % 360; // Conceptual mapping to ecliptic longitude
} else if (calculationType === "IC") {
targetPlanetName = "IC"; // IC is an angular point
var icDegreeApprox = (lstAtBirthLocation * 15) + (birthLon) + 180; // Approximation
eclipticLon = (icDegreeApprox + 180) % 360; // Conceptual mapping to ecliptic longitude
} else if (calculationType === "ASC") {
targetPlanetName = "ASC"; // ASC is an angular point
// ASC/DSC calculation is more complex, related to the zodiac rising
// For simplicity, let's *conceptually* link it to a planet's position for this demo.
// A real ASC line calculation needs the exact Ascendant Degree.
// We'll just use the birth longitude as a proxy for "rising" direction for this simplified demo.
eclipticLon = (lstAtBirthLocation * 15) + birthLon; // Placeholder logic
} else if (calculationType === "DSC") {
targetPlanetName = "DSC"; // DSC is an angular point
// Similarly complex. Placeholder logic.
eclipticLon = (lstAtBirthLocation * 15) + birthLon + 180; // Placeholder logic
} else {
// It's a planet line
if (planetPositionsApprox[calculationType]) {
targetPlanetName = calculationType;
eclipticLon = planetPositionsApprox[calculationType].longitude;
eclipticLat = planetPositionsApprox[calculationType].latitude;
} else {
resultDiv.innerHTML = "Invalid line type selected.";
return;
}
}
// — Conceptual Line Intersection Calculation —
// The goal is to find a longitude (Lon_Line) such that at the `currentLat`,
// the `targetPlanet` (or MC/IC) aligns angularly.
var calculatedLineLongitude = "N/A";
var intersectionDescription = "";
if (targetPlanetName === "MC") {
// Approximate longitude where MC is at the zenith
// MC = LST + Longitude. We want to find Longitude_Line such that MC = TargetPlanetRA/Dec
// This is highly simplified. A true MC line calculation traces where MC DEGREE = BIRTH MC DEGREE
// For this demo, we'll simplify: assume MC line follows approximately a path where the MC degree calculation matches the birth MC degree.
calculatedLineLongitude = ( ( (lstAtBirthLocation * 15) + birthLon ) % 360 ) ; // This is just the MC longitude itself, not a line tracing
intersectionDescription = "The MC line represents locations where your career and public image energies are most prominent. On this line, your Midheaven point aligns with the sky's zenith.";
} else if (targetPlanetName === "IC") {
// Similar simplification for IC line
calculatedLineLongitude = ( ( (lstAtBirthLocation * 15) + birthLon + 180) % 360 ) ; // Conceptual IC longitude
intersectionDescription = "The IC line relates to your home, family, and inner foundations. On this line, your Immum Coeli point aligns with the sky's nadir.";
} else if (targetPlanetName === "ASC") {
// Similar simplification for ASC line
calculatedLineLongitude = ( ( (lstAtBirthLocation * 15) + birthLon ) % 360 ); // Conceptual ASC longitude
intersectionDescription = "The Ascendant line influences your personality, first impressions, and how you interact with the world. On this line, the zodiac sign rising on the eastern horizon at your birth is prominent.";
} else if (targetPlanetName === "DSC") {
// Similar simplification for DSC line
calculatedLine Longitude = ( ( (lstAtBirthLocation * 15) + birthLon + 180) % 360 ) ; // Conceptual DSC longitude
intersectionDescription = "The Descendant line governs your relationships and partnerships. On this line, the zodiac sign setting on the western horizon at your birth is prominent.";
} else {
// For planet lines, we need to find the longitude where the planet is angular.
// This is complex. A very rough approximation: calculate where the planet *would be* at the MC/ASC position at the birth location.
// We'll simplify further: assume the line follows a path of constant ecliptic longitude for the planet.
// This isn't strictly astrocartography, but demonstrates a calculation.
// A real AC line calculation finds longitude_line where planet's RA/Dec align angularly with LAST(longitude_line).
// For demonstration, let's assume the line follows a path where the planet's ecliptic longitude is constant.
// This is a HUGE simplification.
calculatedLineLongitude = eclipticLon; // Assume line is drawn at the planet's ecliptic longitude.
intersectionDescription = `The ${targetPlanetName} line is associated with ${targetPlanetName.toLowerCase()}'s energies: ${planetPositionsApprox[targetPlanetName] ? planetPositionsApprox[targetPlanetName].description || 'general influence' : "}.`;
}
// Format the output
var formattedBirthLat = formatDegrees(birthLat);
var formattedBirthLon = formatDegrees(birthLon);
var formattedCurrentLat = formatDegrees(currentLat);
var formattedCurrentLon = formatDegrees(currentLon);
var formattedLineLon = formatDegrees(calculatedLineLongitude);
// Check if the current latitude is "on" the calculated line longitude conceptually
// This check is symbolic as lines are not straight east-west paths.
// We'll indicate if the current location's longitude is 'near' the calculated line longitude for conceptual purposes.
var proximityThreshold = 10; // degrees
var isNearLine = Math.abs(currentLon – calculatedLineLongitude) < proximityThreshold || Math.abs(currentLon – (calculatedLineLongitude + 360)) < proximityThreshold || Math.abs(currentLon – (calculatedLineLongitude – 360)) < proximityThreshold;
var outputHTML = "";
if (targetPlanetName === "MC" || targetPlanetName === "IC" || targetPlanetName === "ASC" || targetPlanetName === "DSC") {
outputHTML = "Birth Location: " + formattedBirthLat + ", " + formattedBirthLon + "";
outputHTML += "Current Location: " + formattedCurrentLat + ", " + formattedCurrentLon + "";
outputHTML += "Calculated " + targetPlanetName + " Line Longitude (Approx): " + formattedLineLon + "";
outputHTML += "Interpretation: " + intersectionDescription + "";
outputHTML += "This calculator provides a conceptual estimate. The calculated longitude represents a theoretical point where the " + targetPlanetName + " line might pass through your birth location's chart context. Actual astrocartography maps trace these lines continuously across the globe.";
} else {
outputHTML = "Birth Location: " + formattedBirthLat + ", " + formattedBirthLon + "";
outputHTML += "Current Location: " + formattedCurrentLat + ", " + formattedCurrentLon + "";
outputHTML += "Approximate " + targetPlanetName + " Line Longitude: " + formattedLineLon + "";
outputHTML += "Interpretation: " + intersectionDescription + "";
outputHTML += "This calculator provides a conceptual estimate. The calculated longitude represents a theoretical path where the " + targetPlanetName + " energy is emphasized. Actual astrocartography maps trace these lines continuously across the globe.";
}
resultDiv.innerHTML = outputHTML;
}