Indian Institute of Astrophysics (IIA), an autonomous body under the Department of Science and Technology, played a crucial role in the Surya Tilak Project at Ayodhya.  Under the Surya Tilak project, sunlight was brought on the forehead of Sri Ram Lalla at 12 noon on the occasion of Sri Ram Navami in the Chaitra month.  IIA team carried out the calculation of the sun position, design and optimisation of the optical system, and performed the integration & alignment at the site. The English calendar date of Sri Ram Navami festival changes every year as it follows the Lunar Calendar. Therefore, the position of the sun on the sky changes every year on the day of Sri Ram Navami. Detailed calculations show that the English calendar date of Sri Ram Navami repeats every 19 years. Calculating the position of the sun in the sky on these days requires expertise in astronomy.