Hello Mahesh,

The eligibility criteria for studying M.Sc Astronomy is that the candidate must have passed with good grade or percentage in 10+2 or equivalent exam from a recognised Board.

Also students who have taken Physics as main subject in Bachelor of Science (B.Sc) degree are eligible for studying M.Sc. Astronomy.

So if you have taken Physics as main subject in your B.Sc Undergraduation degree then you are eligible for M.Sc Astronomy if not you are not eligible.

Hope this helps.
All The Best!!