Guess what is unique about the Ram Navami of 17 April this year, and every year thereafter? The Shri Ram temple, which was unveiled by the Prime Minister Narendra Modi on 22 January in Ayodhya, will have a unique ‘Surya Tilak’ on the forehead of the idol of Lord Ram every Ram Navami.
Tilak, a traditional Hindu mark worn on the forehead, will be quite literally inked by the rays of the sun on the forehead of the idol of Ram Lalla at around 12 noon for six minutes, on Ram Navami, the festival celebrating the birth of Lord Ram, every year.
This scientific marvel has been achieved by scientists of the Indian Institute of Astrophysics (IIA), who have designed a special mirror- and lens-based apparatus, which will ensure that every Ram Navami at noon, a ray of sunlight falls directly on the forehead of the Ram Lalla statue for six minutes. The IIA team was involved in monitoring the implementation of the project, and provided technical expertise in the testing, assembly, integration and validation of the system.
Under the Surya Tilak project, sunlight will be brought on the forehead of Lord Ram at 12 noon on Sri Ram Navami in the Chaitra month (of Indian calendar or Saka Samvat) every year. The English calendar date of Sriram 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.
The IIA team made the calculations of two different things. First, it identified the calendar days of Ram Navami for one cycle of 19 years, followed by its repetition. Secondly, it estimated the position in the sky on the calendar dates of the Ram Navami.
Scientists of Indian Institute of Astrophysics along with CSIR-CBRI have designed a mirror- and lens-based apparatus to ensure that a ray of sunlight falls directly on the forehead of the Ram Lalla idol every Ram Navami at noon
Moreover, the IIA team led various designs needed for the project. The designs included optical design of an opto-mechanical system to direct the sunlight from the top of the temple to the forehead of the idol. It was followed by estimation of the size, shape and location of mirrors and lenses in the system for sufficient light to fall on the idol for about 6 minutes.
Similarly, opto-mechanical design of the lens and mirror holder assembly and manual mechanism to shift the position of the first mirror according to the position of the Sun in the sky were also executed by the IIA team. Moreover, the IIA team also performed design optimisation as well as simulations to arrive at various quantities in the opto-mechanical design and the functioning of the mechanism.
“The above mechanism was designed to work even if there is a shift of 1-2 days in the calendar date of the Ramanavami. A change will alter the duration of the spot on the idol,” says Dr Annapurni Subramaniam, director, Indian Institute of Astrophysics.
However, she made it clear that the mechanism will not work if there is no sunlight due to clouds or rain. Also, an annual shift of the first mirror has to be performed manually before Rama Navami every year. The lenses and mirrors mounted on holders are accessible and can be cleaned periodically, she added.
The optomechanical system, stationed on the third floor of the temple, comprises high-quality mirrors and lenses arranged in a specific sequence to channel sunlight onto the idol. The system’s design accounts for the changing position of the sun on Ram Navami each year, ensuring accuracy for the ritual. “The team of CBRI (Central Building Research Institute, Roorkee) has developed the mechanism with a 19-year period to steer the sunlight from the third floor of the temple to the Garbha Griha (sanctum sanctorum), in consultation with the Indian Institute of Astrophysics, Bengaluru. The detailed complete design to bring the sunlight to the Garbha Griha is developed by CBRI, with the Indian Institute of Astrophysics providing consultancy for the optical design,” says Dr SK Panigrahi, chief scientist of the project.
The optical design validation, fabrication of optical elements, pipes, tilt mechanism and other related components are carried out by Optics Allied Engg Pvt. Ltd (Optica), a Bengaluru-based company. Optica will install the whole system in the temple in the presence of the CSIR-CBRI team with Indian Institute of Astrophysics providing necessary consultation.
“The installation part inside the Garbha Girha has already been completed. The structural analysis and design of Shri Ram Mandir at Ayodhya has been performed by CSIR-CBRI,” said Dr Debdutta Ghosh, Senior Scientist, CSIR- CBRI Roorkee.
The structural design also meets the provision for required opening and passages for the Surya Tilak of Shri Ram Lalla on occasion of each year on Shri Ram Navami.
Variation of Ram Navami dates in the tropical solar calendar posed the biggest challenge before the scientists involved in the project. Since a lunar year of 12 lunar months is shorter than a solar year by nearly 11 days, a specific lunar tithi (date) like Rama Navami shifts to an earlier date during successive years. Hindu lunisolar calendar applies a correction through Adhik Mas (intercalary month) every 2-3 years to bring back lunar months closer to the seasons which are aligned fully with the solar calendar. If Ram Navami takes place after Adhik Mas, the Tithi jumps to a later solar date and drifts back until the next Adhik Mas. As you can see, the Ram Navami dates stay within the range of March 25 and April 21 according to Hindu Calendar App developed by Alok Mandavgane.
The length of 19 solar (tropical) years is very close to 19 times 12 lunar months and 7 intercalary months. Thus, Hindu lunisolar calendar Tithi repeats after a 19-year cycle. Therefore, a cyclical arrangement of 19 positions will be sufficient. A mechanism is designed to direct the sunlight in a specific direction at a specific time (such as local noon) on a specific Tithi, that can be manually adjusted every year.
“The elevation angles of the Sun at local noon on these 19 positions were provided by the Indian Institute of Astrophysics (IIA), Bengaluru,” says Dr Tushar Prabhu, retired senior professor at IIA.
Interestingly, the project involves no electricity, battery, iron, or steel. It is a manually operated system made of brass, maintaining the traditional ethos of the temple.
*The writer is a senior journalist and Associate Professor, DY Patil International University, Akurdi, Pune.
