Inter-University Centre for Astronomy and Astrophysics

If you really want to do astronomy it's very good so study at least physics and maths in class 11th and class 12th. Do a B.Sc in Physics and take a few elective courses in astronomy/astrophysics. After that do your postgraduate studies in astronomy/astrophysics.

You can't apply for PhD after B.Tech. You need to pursue PG after B.Tech and then, after post graduation, you'll be eligible to apply for PhD.

Yes, you can do M.Sc in astrophysics after B.Sc.
Good luck.

Yes you can definitely go for M.Sc. after graduated automobile engineering and there are numerous opportunities available after M.Sc. you can you can go for becoming research personal by taking a carrying out your PST and after Masters and you can definitely you should definitely go for internships as much as possible because internships give you good in sight words what you think you can do there are a number of opportunities available do research on internet browser scholarships about courses about about internship opportunities training programs that help you a lot. All the best