M.Sc Physics

The diploma wouldn't fetch you much, especially a distance one. If you really want to make career in Astronomy and AstroPhysics, you should rather opt for M.Sc and PhD.

For the syllabus, please visit the link given below:
https://www.shiksha.com/university/tezpur-university/tuee-exam-syllabus

St. Xavier's College, Kolkata offers M.Sc in physics, but I don't think so, astronomy is there as a specialization.

The eligibility is, candidate must have completed B.Sc with Physics from a recognized University. The classes schedule is normal from around 9.30 AM to 5.00 PM.

From my experiences, I can tell you that there is no specific book which can help you or there is no specific book from where they ask questions. Mainly, all the M.Sc Level entrance exam deal with the problems Being a Physics Hons student, I can tell you that to solve this type of problem, you have to clear first your basics. Basically, you need to study various type of book and solve many problems. As you ask which is the best book I will recommend you the book written by S. K TOMAR and you may go through all the study material of FIZIKS.

Visit the below mentioned link:
https://www.shiksha.com/science/colleges/m-sc-physics-colleges-Punjab

Please use the link provided below a detailed list of entrance exams for a course in M.Sc Physics conducted by authorities in India. https://www.shiksha.com/science/articles/top-bsc-msc-entrance-exams-in-india-blogId-13484.

You may get some help here: http://www.thealigarian.com/amu-previous-year-question-papers-pdf/.

You can get previous years question papers of integrated M.Sc. In Physics by different Apps like EduRev infinity , Eduncle !