The top picture is a stamp commemorating X’s observation of a phenomenon (later named after him). The images at the bottom depict the place Y where X made his famous observation and the lunar crater named after X. Give X & Y.
Today’s question is contributed by Sushruth Ravish.
Good crack by Anush…It is the Evershed effect named after John evershed(X) and Y is the Kodaikanal observatory currently under Indian Institute of Astrophysics