Astronomy

An astronomer' primary job is to find answers of unexplained astronomical events, in other words to explain the physics of the events.
Hence, to make a career in astronomy/astrophysics, you need tofocus on physics, mathsand, to an extent, chemistry as well.You'll be required to do BSc and MSc in physics.Masters can be done with specialization in any physical science subject like Material Science, Applied Physics, Electronics etc. However, you should be reasonably clear with your understanding of Classical Mechanics, Electrodynamics, Quantum Mechanics, Statistical Mechanics and Mathematical Physics as these are the fundamental subjects in Physics.
Few universities also offer MSc in astronomy. You can also do that after your BSc in physics. During the summer vacations after your BSc or during the MSc you can apply to national research institutes in India, where they do research in astronomy, for summer internship. This will give you flavour of the environment in research institutes as well as help build up your CV. Please make sure you grades are good, as that helps in getting these intern-ships, though they are not the only criteria.Whatever you study during BSc and MSc courses is your basic training for being an astronomer in future.
During and after completing your masters, appear for national level entrance exams like GATE, NET, JEST etc. Some institutes also have their own entrance exams. You need to clear at least one of those with a good percentile to be called for interview. Clear the interview and you'll be offered research scholarship to doPhD on a particular topic in astronomyunder the guidance of a scientist.A PhD can take anywhere from 3-7 years in India. However, most generally take 4-6 years.After that, you can go for post-doctoral research or you can join a research institute or university as a faculty where you can pursue further research. One can even go to international institutes as well for doing PhD.
Some instiutes in India offer integrated MSc after class 12 and some offer integrated PhD after BSc. This is another option.

Hi Rohaan,
Before you decide what to do it is important that you become aware of a critical factor for success in your chosen profession. Your exam scores are one part of it considering how competitive it is to land a seat in the hallowed campuses of the IITs and other prestigious institutions.
There are numerous branches of space science - astronomy, astrophysics, cosmology, stellar science, planetary science etc. Originally, all these disciplines were considered as part of astronomy, but with recent developments and discoveries, they have become vast enough to be considered as separate fields on their own. Experts in fields such as robotics, satellite technology, medicine, biology, remote sensing, meteorolog etc. may also seek careers in space science after developing the skill sets necessary for the job.There are quite a few institutes in India that train students for pursuing careers in space science and technology. The recently established Indian Institute of Space Science and Technology (IIST) offers graduate and postgraduate programs in space science and related fields. Apart from IIST, a few other institutes like the Vikram Sarabhai Space Centre (VSSC), ISRO Satellite Centre (ISAC), Space Application centre (SAC), National Remote Sensing Agency (NRSA), Liquid Propulsion Systems Centre (LPSC) also offer research opportunities in space science and allied fields. Some of the Indian Institutes of Technology (IITs) also offer specialization programs (M.Tech) in Space Technology, Astrophysics, Aerospace engineering etc.The eligibility criteria for joining programs in space science and technology vary according to the specific requirements of each job. Admissions to the undergraduate courses at the Indian Institute of Space Science and Technology (IIST) is made on the basis of a candidate's rank in the Joint entrance Examination conducted by IITs. In other places, candidates with B.Sc., M.Sc., B.E., M.E. or Ph.D. are usually selected. Study of science subjects such as Mathematics, Physics, Chemistry at undergraduate level is usually a mandatory requirement. However, before you join a career in space science, it is necessary for you to know the various requirements of the field - which skills to develop, which courses to take, where to study.
Hope this helps.
Wish you luck.