On May 16, 2025, India Post released a ₹5 commemorative stamp celebrating 125 years of the Kodaikanal Solar Observatory (KSO), a premier solar research facility established in 1899. The stamp, launched at the Indian Institute of Astrophysics (IIA) in Bengaluru, features the historic observatory building and an H-alpha sun image.

Key Details of the 125th Anniversary Stamp:
Release Date: May 16, 2025 (coinciding with the International Day of Light).
Significance: Celebrates KSO’s 125 years of continuous solar data collection (established 1 April 1899).
Design Elements: Features the historic two-dome building, an H-alpha image of the Sun (taken May 6, 2024), and the IIA logo.
Denomination: ₹5.
Officials Present: Released by Shri S. Rajendra Kumar (Chief Postmaster General, Karnataka Circle) and Shri A.S. Kiran Kumar (Chairperson, Governing Council, IIA and former ISRO Chairman)