BDS

Hello,
You can't study M.Sc in astrophysics after BDS directly. I mean you can change your career but you can't get admission directly in M.Sc.
First thing is: - you must have maths in class 12, it's very good if you had.
2nd thing is: - you take some other way that would be good for you I guess, I

Here you can refer this link to get a complete overview of this college:
https://www.shiksha.com/college/apollo-institute-of-hospital-administration-jubilee-hills-hyderabad-24457
Kindly visit the link.

Duration of Diploma will be 2 years only. Good luck.

Duration of Diploma will be 2 years, if you take admission in dual Diploma, then it can take 3 years. Good luck.

Please visit given link for list of good college
https://www.google.com/url?sa=t&source=web&rct=j&url=https://www.shiksha.com/medicine-health-sciences/dental/colleges/bds-colleges-Faridabad&ved=2ahUKEwiHlMTl1aXiAhXn73MBHY6PDA4QFjAMegQIBhAB&usg=AOvVaw21kAqMyIMB3xw3jHgOcqJa.