How to become an Astrophycists?
Education Needed to Become an Astrophysicist-
A Bachelor of Science degree in astronomy, astrophysics or physics may qualify you for entry-level jobs in astrophysics
A Master of Science degree in astrophysics is required for most research assistant and consulting positions.
A doctoral (Ph.D.) degree in astrophysics is most likley needed if you want to work for a college or university as a teacher or a researcher. You will also likely need a Ph.D. to work in most federal government research positions. Many astrophysicists who have doctoral degrees work as post-doctoral fellows for 3-6 years before finding permanent employment.
These best institutes in India for Physics & Astronomy were selected basis academic reputation, employer reputation and research impact.
Indian Institute of Technology, Bombay (IITB)
Tata Institute of Fundamental Research, Mumbai (TIFR)
University of Delhi (DU)
Indian Institute of Science, Bangalore (IISc)
Indian Institute of Technology, Delhi (IITD)
Indian Institute of Technology, Madras (IITM)
Indian Institute of Technology, Kharagpur (IIT Kharagpur)
Banaras Hindu University, Varanasi (BHU)
Indian Institute of Astrophysics, Kodaikanal & Bengaluru
You can also visit the following link to know more.
https://www.iiap.res.in/opportunities/career
Hope this helps. All the best.

In ISRO, Tata Institute of Research Center (TIFR), and in Bhabha Atomic Research Center (BARC), India, Astrophysist (or any scientist in Officer post or Guide) get salary of about ₹1-2 Lakh.
But in foreign countries salary is quite high.