to become a astrophysicist you must first earn a bachelor degree in the field of astronomy , astrophysics or physics ,

2. then go for masters in same you have pursued your bachelors , as master of science degree in astrophysics is required for most research and consulting positions

3. your Ph.D Degree will be valued much if you like to work in a college or university as a teacher or a researcher , this will also lead you to get a good research positions in government organization

here i am listing some institute offering the same

1. indian institute of technology , bombay (IITB)

2. tata institute of fundamental research, mumbai (TIFR)

3. university of delhi (DU)

4. indian institute of science , bangalore (IISC)

5. indian institute of technology , delhi (IITD)

all the best!