Astronomical observation is the beginning of scientific attitudes in the history of mankind. According to Indian tradition, there existed 18 early astronomical texts (siddhantas) composed by Surya, Pitamaha and many others. Varahamihira compiled five astronomical texts in a book named panchasiddhantika, which is now the link between early and later siddhantas. Indian scholars had no practice of writing their own names in their works, so, it is very dicult to identify them. Aryabhata is the rst name noticed, in the book Aryabhatiya. After this point most astronomers and astro-writers wrote their names in their works. In this paper I have tried to analyze the works of astronomers like Aryabhata, Varahamihira, Brah- magupta, Bhaskara I, Vateswara, Sripati and Bhaskaracharya in a modern context and to obtain an account of Indian astronomical knowledge. Aryabhata is the first Indian astronomer who stated that the rising and setting of the Sun, the Moon and other heavenly bodies was due to the relative motion of the Earth caused by the rotation of the Earth about its own axis. He also estabished the `yuga' theory (one Mahayuga = 432000 years). Varahamihira com- piled panchasiddhantika and wrote Brihatsamhita. Brahmagupta is the most distinguished astronomer known to us. His two major works are i) Brahmasphutasiddhanta and ii) Khandkhadaka. Bhaskara I was the follower of Aryabhata. His three known works are Mahabhaskariya, Laghubhaskariya and Aryab- hatiyabhasya. Vateswara follows Aryapaksha and Saurapaksha. His master work is Vateswarasiddhanta. Sripati, in his siddhantasekhara, gives the rules for determining the Moon's second inequality. Bhaskara II wrote the most comprehensive astronomical work in Indian astronomy. The result of these works is the account of the Indian astronomical heritage. These works are written in the Sanskrit language. A very few of these manuscripts have been translated in English but many are yet to be done. So, it is necessary to translate these astronomical texts into English with proper commentary for modern scholars. This paper will be helpful in this work.

ABSTRACT
1. INTRODUCTION
2. MAIN CONTRIBUTORS TO INDIAN ASTRONOMYDURING THE 5th to 12th CE
    2.1. Aryabhata I (b 476 CE)
    2.2. Varahamihira
    2.3. Brhamagupta
    2.4. Bhaskara I
    2.5. Vateswara
    2.6. Bhaskaracharya
3. CONCLUSIONS
REFERENCES

• Somenath Chatterjee(Sabitri Debi Institute of Technology (School of Astronomy) BANAPRASTHA)