Dear student,

Among the Institutions you have mentioned all of them are top Institutions. You can choose any one of it. But among them IISc would be preferable because of its academics and knowledge shared by the faculty. So for you IISc would be better to do MS Astrophysics. IIST and IICAA are also good you can go with them also if you are personally interested in them.

For more information about IISc go through below link.

http://htters360.com/university/indian-institute-of-space-science-and-technology-thiruvananthapuram/ms-astronomy-and-astrophysics-course

Hope this information helped you.