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PIB Summaries 19 April 2024

  1. Surya Tilak Project


The Surya Tilak Project, a remarkable endeavour, recently unfolded at Ayodhya, bringing sunlight to the forehead of Sri Ram Lalla.


Facts for Prelims

Dimensions of the Article:

  1. Overview of the Surya Tilak Project
  2. Indian Institute of Astrophysics (IIA)

Overview of the Surya Tilak Project

Description and Purpose

  • The Surya Tilak Project is a blend of advanced technology and traditional beliefs. It is designed to focus a precise beam of sunlight on the forehead of Lord Ram’s idol during the auspicious festival of Ram Navami.
  • The project was undertaken by the Indian Institute of Astrophysics (IIA), an institution under the Department of Science and Technology.

Role of IIA

  • The IIA was responsible for calculating the sun’s position, designing, and optimizing the optical system for the project.
  • The project aims to align the sunlight beam with the forehead of Lord Ram’s idol on the variable date of Ram Navami, which is determined by the solar Gregorian calendar, in contrast to the lunar-based Hindu calendar.
Opto-Mechanical System
  • The heart of the Surya Tilak Project is its sophisticated opto-mechanical system, which seamlessly combines optical and mechanical components to manipulate sunlight accurately.
  • Resembling a periscope, the system employs a 19-gear mechanism to make yearly adjustments to account for the sun’s changing position.
  • A manual adjustment, turning one gear tooth each year, is required to set the angle of the pickup mirror.
  • The number 19 is significant as it corresponds to the Metonic cycle, a 19-year period resetting the alignment of the Moon’s phases with the solar year.
  • The Surya Tilak system, equipped with 4 mirrors and 2 lenses, underwent testing, assembly, integration, and validation at the site with technical expertise from IIA.
  • The Central Building Research Institute (CBRI) of the Council of Scientific & Industrial Research (CSIR) was responsible for the on-site implementation of the opto-mechanical system.

Future Plans

  • A revised design of the Surya Tilak with 4 mirrors and 4 lenses is planned for implementation upon the completion of the full temple. This updated design will accommodate the shifting date of Ram Navami in the calendar.

Maintenance and Challenges

  • An annual manual adjustment of the first mirror is required before Ram Navami each year.
  • The system is dependent on clear sunlight and will not function in the absence of direct sunlight due to factors like clouds or rain.

Indian Institute of Astrophysics (IIA)

Establishment and History

  • Founded in 1786 in Madras, the Indian Institute of Astrophysics (IIA) was relocated to Kodaikanal in 1899 and was established as an autonomous institution in 1971.


  • Currently headquartered in Bengaluru, the institute has historical roots in Madras and Kodaikanal.

Funding and Affiliation

  • The institute is financially supported by the Department of Science and Technology and stands as a prominent research and educational hub in the fields of astronomy and physics.

Observational Facilities

  • IIA’s primary observing facilities are strategically located at Kodaikanal, Kavalur, Gauribidanur, and Hanle, enabling a broad range of observational studies.

Research and Development

  • The institute engages in observational studies of solar and atmospheric physics, nighttime astronomy using various telescopes, and the design and development of advanced instruments for astronomical research.

May 2024