Unveil your true astrological identity using the Sidereal system. This calculator uses your exact birth data to determine your core signs and placements, based on the fixed star constellations.
Sidereal Astrology Chart Calculator
Your Primary Sidereal Placement:
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Sidereal Astrology Chart Basis
Ayanamsa (Lahiri) $\approx 23^\circ 59′ 17”$ (Epoch 2024.0)
Formula Source: Ayanamsa Principle (Wikipedia), Zodiac Difference (Astro.com)
Variables
The Sidereal Chart Calculator requires four crucial inputs for precise computation:
- Date of Birth (DOB): Essential for finding the Sun’s position in the sky at the time of birth.
- Time of Birth (TOB): Critical for determining the Ascendant (Rising Sign) and the specific house cusps.
- Birth Latitude: Specifies the vertical location on Earth, affecting the angle of the Ascendant.
- Birth Longitude: Determines the time zone and local sidereal time (LST), crucial for charting the planets.
Related Calculators
Explore other astrological and time-based calculations:
- Tropical Birth Chart Calculator
- Rising Sign Finder
- Planetary Returns Calculator
- House System Converter
What is Sidereal Astrology?
Sidereal astrology is a system that aligns the zodiac signs directly with the actual, visible constellations in the night sky. Unlike Tropical astrology, which is based on the seasons (the spring equinox), the Sidereal system accounts for the slow, westward shift of the Earth’s axis, known as the precession of the equinoxes. This difference—the Ayanamsa—results in sidereal signs often being about 23-24 degrees behind the tropical signs.
The Sidereal chart provides a perspective that many find more connected to the physical, fixed universe. Your sidereal placements are considered by practitioners to reflect deeper, more stable karmic traits, as opposed to the more personality-driven tropical placements.
How to Calculate a Sidereal Chart (Conceptual Example)
While this calculator automates the process, here is the underlying conceptual procedure:
- Determine the Birth Data: Collect the precise Date, Time, and Coordinates (Latitude/Longitude) of birth.
- Calculate Local Sidereal Time (LST): Convert the birth time and location into LST, which is necessary to determine the degree of the Ascendant.
- Find Planetary Positions (Tropical): Using astronomical tables (ephemeris), calculate the exact celestial longitude of the Sun, Moon, and all planets in the Tropical Zodiac for the birth moment.
- Apply the Ayanamsa: Subtract the specific Ayanamsa value (the accumulated measure of precession) for the date of birth from all the calculated Tropical planetary positions. This shifts the planets into their Sidereal positions.
- Determine House Cusps: Use the LST and the birth coordinates (usually Placidus or Koch house system) to define the boundaries of the 12 astrological houses.
- Chart Synthesis: Assemble all the Sidereal placements and house cusps into the final chart.
Frequently Asked Questions (FAQ)
Is the Sidereal chart more accurate than the Tropical chart?
Accuracy is subjective and depends on the school of astrology. Sidereal (often used in Vedic or Eastern traditions) bases its signs on the physical constellations, while Tropical (Western) bases them on the seasons. Both systems are internally consistent; the “best” one is the one that resonates most with the user.
What is an Ayanamsa?
The Ayanamsa is the mathematical difference in longitude between the beginning of the Tropical Zodiac (0° Aries, the spring equinox) and the beginning of the Sidereal Zodiac (the actual fixed star Spica/Chitra). It is the correction factor for the precession of the equinoxes.
Why do I need my exact time of birth?
The time of birth is crucial for determining the Ascendant (the sign rising on the Eastern horizon at that moment), which changes rapidly—a degree every four minutes. The Ascendant defines the entire structure of the astrological houses.
Can I use my city name instead of coordinates?
For high precision, coordinates are best. While many services allow city names, they simply convert the city name to coordinates. This calculator requires direct input of Latitude and Longitude for exactness.