Hello there, aspirant

For astrophysics, IISER only accepts BS-MS on the basis of JEE advanced, KVPY, and SCB.

It accepts PhD applicants through the GATE/JEST test.

Check out the Indian Institute of Astrophysics if you wish to pursue a master's degree in astrophysics.

IISER only accepts students who have completed a BS-MS programme at their institution.

I hope this information is useful.

All the best.