You should go for Astronomy. Astronomy is the scientific study of celestial Bodies. It is a sub Branch of Physics which studies the universe as a whole. Courses offered in Indian in this field are MSc in Astronomy and PhD. In Indian, It is recommended that first You complete Your Graduation in Science, With Physics as a subject or Mathematics, Even Engineering with Electrical Branches. After Graduation You can apply to the following Institutes.

1 Indian Institute of Astrophysics, Bangalore

2 SN Bose National Centre for Basic Science Kolkata.

3 Tata Institute of Fundamental Research, Pune

4 Madurai Kamaraj University, Madurai