I am asked this question a lot. Here I list main differences, so you'll never get puzzled by words “vedic” and “jyotish” again.
Short answer: Vedic astrology uses more accurate astronomical data to calculate the chart. So if you looked up at the sky at the time and place of your birth, Vedic astrology would use precise planet positions for your birth chart.
Longer answer: Vedic astrology uses Sidereal zodiac, Western astrology uses Tropical zodiac. Zodiac is the path that Sun travels through over the course of 1 year. This path is divided into 12 parts, or zodiac signs. Planets transit along zodiac. Astronomically speaking, the actual position of the Sun against that path shifts every century by 1.4 degrees. This is called precession. 2000 years ago Sidereal and Tropical systems used the same point to calculate the beginning of zodiac. However, over time, due to precession this point has shifted by 24 degrees. Vedic astrology takes into account this difference, while Western astrology does not. So Vedic Astrology chart will show more accurate picture of stars in the heaven at the time of your birth according to astronomy. Due to 24 degrees difference, planets position, houses and rising signs will be different from Western Astrological chart. This is also a reason why new/full moon happen in different signs from Western Astrology.
Vedic astrology was originated in India, Western astrology was originated in Greece. The word "Vedic" comes from a term “Vedas", ancient Indian writings of the yogis and sages. It is part of a complex and very sophisticated system of teachings that include philosophy, astronomy, mathematics, grammar and other sciences.
Vedic astrology is just a western term for Jyotish, which means “the lord if light” as it shines the light on the person’s life. It is called “eye of the Vedas”, because it allows you to see where you are going.
Jyotish, being a part of the Vedas, has intricate and sophisticated philosophy behind it. Vedic astrology readings are based on ideas of karma and dharma, unity of mind-body-soul, reincarnation, as well as understanding that you are a microcosm of a larger Universe. So when you get jyotish reading, you are connecting to the knowledge of the Vedas instead of homespun philosophy or personal opinions of individual astrologer. One of the task of Jyotishi (Vedic astrologer) is to continuously learn about philosophy, yoga, meditation in order to integrate and be able to explain what is seen in the chart from Vedic point of view.
In Jyotish, we use nine planets: Sun, Moon, Mercury, Venus, Mars, Jupiter, Saturn, and two shadow planets that have no physical body, Rahu and Ketu. The shadow planets constitute karmic imprints in a person’s chart and have paramount importance for horoscope interpretation. Western astrology does not use Rahu and Ketu, but includes outer planets, such as Uranus, Neptune, and Pluto.
Jyotish has unique system of prediction based on planetary periods that influence your chart at any point in time. It explores the cycles of human life and allows to look at it in a dynamic way, where energies change and shift all the time.
They are 27 lunar constellations that show how energy of the planets manifests itself depending on the degree it occupies in the sign. Planet in the same sign but in different degrees can show varying results. Nakshatras' rich symbolism and mythology provide infinite material for chart interpretation.
Vargas or divisional charts
Use of divisional chart called Vargas is another distinguishing feature of Vedic Astrology. They provide deeper insights into various domains of life. The most important divisional chart is called Navamsha, which is used for interpretation of general direction of person’s life, relationships, and spirituality.