In the practice of astrology, there are two main types: Western, also known as tropical astrology, and Vedic, also known as sidereal astrology. This article explores the main differences between the two traditions.

Calculating the Positions of the Planets and Stars

The Sidereal Method

Although Western astrology traces its roots to the cultures of Ancient Egypt and Greece, the practice of astrology was going on in India long before these civilizations came into being.

Traditionally, Indian astrologers calculated planetary positions based on the fixed locations of the stars in the sky. In the same way that the pole star has always been used to determine true North, various constellations were used to measure the movement of the planets along the ecliptic.

However, due to the precession of the equinoxes, Indian astrologers adjusted their calculations to keep in sync with the stellar positions. Thus, their system is known as sidereal, or star-based.

The Tropical Method

Around 285 B.C, the Greek astronomer Ptolemy introduced a simplified method of calculating the movements of the planets. He noticed that each planet moved in a fixed rate relative to the Sun. By noting the precise times of the fall and spring equinoxes, and the winter and summer solstices, Ptolemy was able to derive the positions of all the other planets.

In this way, Ptolemy conceived what is now known in Western astrology as the tropical method, or judging planetary positions based on the Sun’s movement from the equator to each of the tropics.

At the time, it so happened that in India, there was a perfect alignment between the Sidereal and Tropical methods. Nowadays, however, the corrective adjustment used in Sidereal astrology is about -24 degrees, or almost an entire sign of the zodiac.

What’s Included in a Horoscope?

Another major difference between Vedic and Western astrology is which planets and stars are included in a horoscope. Here’s a list showing what is commonly considered in each of the two systems:

Vedic Astrology

  • The Sun
  • The Moon
  • Mars
  • Mercury
  • Jupiter
  • Venus
  • Saturn
  • Rahu
  • Ketu
  • 27 different Nakshatras, or Lunar Mansions

Western Astrology

  • The Sun
  • The Moon
  • Mars
  • Mercury
  • Jupiter
  • Venus
  • Saturn
  • Uranus
  • Neptune
  • Pluto
  • Asteroids such as Ceres, Juno, and Vesta, and the comet Chiron

Notice that the list starts to diverge after the planet Saturn. The Nakshatras, for instance, are a unique feature of Vedic astrology. These are the “lunar mansions,” or specific sets of stars that the moon passes through in its orbit around the earth. Each one is said to possess a different personality, as well as different strengths and weaknesses, much like the individual zodiac signs themselves.

In addition, Vedic astrologers track the movement of “shadow planets” Rahu and Ketu, which are believed to cause eclipses.

In Western astrology, Uranus, Neptune, and Pluto are used in place of Rahu and Ketu to signify such qualities as obsession, rebellion, and chaos.

Defining the Houses

Both Western and Vedic astrology split a chart into twelve houses, with the first house located on the eastern horizon. However, beyond this point, the traditions each take their own approach. In this section, we’ll look at two aspects of the houses: measurement, and planetary lordship.

How the Houses are Measured

In Vedic astrology, each house is assigned an equal 30°. Generally, Vedic astrologers use what is known as the Whole Sign method of determining houses. This means that if Cancer is the predominating sign in the third house, then a planet that falls anywhere within Cancer’s thirty degree range will be considered a tenant of the third house.

By contrast, in Western astrology, there are several competing ways of measuring out the twelve houses, and they may not all be given an equal number of degrees. Some astrologers follow the Vedic method of equal division, while others adjust the size of the houses based on various factors, such as latitude and the number of daylight hours.

Which Planets Rule Each House

Here is a breakdown of which planets rule each sign according to both systems:

The Twelve Signs

Aries
Taurus
Gemini
Cancer
Leo
Virgo
Libra
Scorpio
Sagittarius
Capricorn
Aquarius
Pisces

Vedic Planetary Lord

Mars
Venus
Mercury
The Moon
The Sun
Mercury
Venus
Mars
Jupiter
Saturn
Saturn
Jupiter

Western Planetary Lord

Mars
Venus
Mercury
The Moon
The Sun
Mercury
Venus
Pluto
Jupiter
Saturn
Uranus
Neptune

Note that in the Western system, Scorpio, Aquarius, and Pisces are assigned to Pluto, Uranus, and Neptune respectively, whereas in the Vedic system, these planets aren’t included at all.

Predicting Life Events

Another significant difference between Western and Vedic astrology is in how each offers predictions of a person’s future life. First we’ll take a look at the core philosophical differences which undergird each system, and then at the methods of predictions themselves.

Different Philosophies

For most practitioners of astrology in the western world, Vedic astrology is viewed as a rather harsh system. Traditional Vedic astrological texts often list terrible outcomes for specific planetary positions and combinations, and a person unfamiliar with the system might be understandably put off.

For example, the textbook outcome of a somewhat common planetary combination known as Daridra Yoga is that the person will “contact huge debts, will be very poor, will suffer from auditory troubles, and will commit sinful and criminal deeds.” (see B.V. Raman’s book, 300 Important Combinations)

However, a skilled astrologer does not take one single piece of information alone, but is instead very careful to analyze the chart as a whole in order to see the overall tendencies of the person.

Vedic culture in general takes what could be termed a “realist” approach to human life — the Vedas do not encourage blind optimism. It is considered far better to have a sober assessment of one’s risks and weaknesses than to naively pretend such things simply aren’t there.

Western astrology, on the other hand, prefers to focus on positive messages and outcomes, emphasizing a person’s strengths, rather than shining light on their weaknesses. Unlike Vedic astrology, which classifies both planets and houses as either “malefic” or “benefic,” Western astrologers prefer to take a neutral view.

Methods of Prediction

In Western astrology, personal predictions rely primarily on what are known as planetary transits. A transit refers to when a given planet passes through a specific sign. In a person’s horoscope, each house is occupied by a single sign. When a planet crosses into that sign, then it will exert greater influence on that house.

In Vedic astrology, predictions follow what is known as the vimshottari dasha system. This system divides a person’s life into nine planetary periods based on their birth nakshatra. For example, if a person is born under Hasta nakshatra, then they would begin life in their Moon period, because Hasta is ruled by the moon. The dasha periods always follow a specific order, and each period lasts a set number of years:

  • The Sun (6 years)
  • The Moon (10 years)
  • Mars (7 years)
  • Rahu (18 years)
  • Jupiter (16 years)
  • Saturn (19 years)
  • Mercury (17 years)
  • Ketu (7 years)
  • Venus (20 years)

Vedic astrologers analyze the positions of each planet in the birth chart in order to determine what major life events are likely to take place during a specific planetary period.

Other Differences

In addition to the major distinctions between Vedic and Western astrology covered above, here are a few more differences which play a significant role in interpreting an astrological chart:

Aspects

A planetary aspect occurs when one planet is directly across from another planet in the chart (180°). They can also occur when planets are a set angle from one another, such as 60°, 90°, or 120°.

In Western astrology, aspects are measured based only on degrees. For instance, if Jupiter is 15° into Leo, and Venus is 16° into Scorpio, then it would be considered a strong aspect.

In Vedic astrology, aspects are measured by the entire house. It doesn’t matter how many degrees a planet has traveled through the sign. For example, if Saturn is in the first house, and Mercury is in the third house, then Saturn would aspect Mercury. In addition, Vedic astrologers only consider certain aspects, depending on the planet. The following table shows the houses over which each planet has full and partial aspects:

Planet100% Aspect75% Aspect50% Aspect25%
The Sun7th4th and 8th5th and 9th3rd and 10th
The Moon7th4th and 8th5th and 9th3rd and 10th
Mars7th, 4th, and 8thN/A5th and 9th3rd and 10th
Mercury7th4th and 8th5th and 9th3rd and 10th
Jupiter7th, 5th, and 9th4th and 8thN/A3rd and 10th
Venus7th4th and 8th5th and 9th3rd and 10th
Saturn7th, 3rd, and 10th4th and 8th5th and 9thN/A

Yogas

In Vedic astrology, an important element of judging the strength of a chart and the overall quality of a person’s life are planetary combinations, known in Sanskrit as yogas. These are special combinations are believed to produce positive or negative results in a person’s life. Some yogas indicate material happiness, others foretell spiritual growth, while some warn of obstacles that may impact different spheres of life.

Western astrology does not incorporate this feature of Vedic astrology.

Directional Strength

Another element of Vedic astrology that doesn’t appear in the Western practice is what is known as directional strength. Each planet performs at its best on a certain side of the chart. Below you can see the table of where each planet is at its strongest:

PlanetStrongestWeakest
The SunThe Tenth HouseThe Fourth House
The MoonThe Fourth HouseThe Tenth House
MarsThe Tenth HouseThe Fourth House
MercuryThe First HouseThe Seventh House
JupiterThe First HouseThe Seventh House
VenusThe Fourth HouseThe Tenth House
SaturnThe Seventh HouseThe First House

Which Astrological Approach Should I Use?

This is up to you! Different people prefer Vedic or Western astrology for different reasons, and the debate over which one is “correct” is unlikely to be conclusively resolved anytime soon.

On our website, we provide astrological information based on the Vedic approach, as we find it to be more accurate, more in-depth, and more consistent across practitioners. This is because the tradition of Vedic astrology has remained intact for thousands of years, whereas Western astrology only regained popularity in the early 20th century.