Here is the "Table of Content" or Index of the Surya Siddhantha. Decide for yourself.
1. The mean motion of the Planets
2. True places of the Planets
3. Direction, Place and Time
4. The Moon and Eclipses
5. The Sun and Eclipses
6. The projections of Eclipses
7. Planetary Conjunctions
8. Of the Stars
9. Risings and Settings
10. The moon’s risings and Settings
11. Certain malignant aspects of Sun and Moon
12. Cosmology, Geography and Dimensions of Creation
These are the DATA the Surya Siddhantha gives,
- The average length of the tropical year as 365.2421756 days, which is only 1.4 seconds shorter than the modern value of 365.2421904 days.
- The average length of the sidereal year, the actual length of the Earth’s revolution around the Sun, as 365.2563627 days, which is virtually the same as the modern value of 365.25636305 days.
- Surya Siddhanta also states the motion, and diameters of the planets! For instance the estimate for the diameter of Mercury is 3,008 miles, an error of less than 1% from the currently accepted diameter of 3,032 miles. It also estimates the diameter of Saturn as 73,882 miles, which again has an error of less than 1% from the currently accepted diameter of 74,580.
- Aside from inventing the decimal system, zero and standard notation (giving the ancient Indians the ability to calculate trillions ) the Surya Siddhanta also contains the roots of Trigonometry.
- It uses sine (jya), cosine (kojya or “perpendicular sine”) and inverse sine (otkram jya) for the first time.
- “Objects fall on earth due to a force of attraction by the earth, therefore the earth, the planets, constellations, the moon and the sun are held in orbit due to this attraction”. (this was also discussed in Prasnopanishad)
- The Surya Siddhanta also goes into a detailed discussion about time cycles and that time flows differently in different circumstances, the roots of relativity.
- It represents mathematical formulae to calculate the orbits, diameters, predict their future locations and cautions that the minor corrections are necessary over time to the formulae for the various astronomical bodies.
Here are some more FACTS from the Surya Siddhantha,
- Surya Siddhanta states that the sidereal period of moon is 27.322 which compares to 27.32166 in modern calculations.
- For Mercury it states the period to be 87.97 (modern W: 87.969), Venus 224.7 (W: 224.701), Mars as 687 (W: 686.98), Jupiter as 4,332.3 (W: 4,332.587) and Saturn to be 10,765.77 days (W: 10,759.202).
- The Surya Siddhanta also estimates the diameters of the planets. The estimate for the diameter of Mercury is 3,008 miles, an error of less than 1% from the currently accepted diameter of 3,032 miles.
- It also estimates the diameter of Saturn as 73,882 miles, which again has an error of less than 1% from the currently accepted diameter of 74,580.
- Its estimate for the diameter of Mars is 3,772 miles, which has an error within 11% of the currently accepted diameter of 4,218 miles.
- It also estimated the diameter of Venus as 4,011 miles and Jupiter as 41,624 miles, which are roughly half the currently accepted values, 7,523 miles and 88,748 miles, respectively.