KODAIKANAL SOLAR OBSERVATORY 

• Since ancient times, the study of the Sun and its celestial activities has captivated seafarers, mathematicians, astronomers, and physicists alike. In a significant development in 1792, the British East India Company established the Madras Observatory, marking a pioneering venture in this part of the world.
• At the Madras Observatory, between 1812 and 1825, meticulous astronomical observations of the Sun, Moon, bright stars, and planets were meticulously recorded and preserved in two extensive data volumes. Subsequently, in 1878, dedicated solar observations commenced from the Trigonometrical Survey Office in Dehradun, further advancing the field of astronomy in India.
• During this era, astronomy primarily revolved around special celestial events such as eclipses or planetary transits, which garnered immense interest from foreign astronomers. Some of these visitors eventually settled in India, contributing significantly to the establishment of observatory-based astronomy within the country.
• Noteworthy breakthroughs emerged from these observations. Spectroscopic observations conducted during the total solar eclipse on August 18, 1868, from Guntur in Andhra Pradesh, led to the groundbreaking discovery of helium, the second-most abundant element in the universe after hydrogen.
• Another milestone was reached during the total annual solar eclipse on December 12, 1871, when celestial and solar photography were attempted for the first time at the Madras Observatory. This historic event marked a pivotal moment in the annals of solar observation, showcasing India's burgeoning prowess in astronomical research and photography.

3. Unraveling the Links to the Great Drought

• The winter monsoon of 1875 cast a shadow over south India as scanty rainfall triggered one of the most devastating droughts witnessed in the country's history. Across the famine-stricken regions of the Madras and Mysore Provinces, multiple crop failures ensued, leading to an unprecedented humanitarian crisis. Estimates suggest that between 12.2 to 29.3 million lives were lost from 1875 to 1877.
• India found itself in the company of several other nations, including China, Egypt, Morocco, Ethiopia, southern Africa, Brazil, Colombia, and Venezuela, as they all grappled with concurrent multi-year droughts from 1876 to 1878. This period, later dubbed the Great Drought, was accompanied by a global famine that claimed the lives of nearly 50 million people.
• The causes of this catastrophic drought were manifold, encompassing various climatic phenomena. Solar activity, coupled with cool Pacific Ocean conditions, set the stage for the crisis. Subsequently, a record-breaking El Nino event in 1877-1878 exacerbated the situation, amplifying the impact of the drought across affected regions. Additionally, strong Indian Ocean Dipole and warm North Atlantic Ocean conditions further compounded the severity of the drought, creating a perfect storm of climatic anomalies.
• The Great Drought of 1876-1878 serves as a poignant reminder of the interconnectedness of global climate systems and the profound implications of climatic disruptions on human societies. It underscores the imperative for concerted international efforts to mitigate the impact of such extreme weather events and build resilience in vulnerable regions.

4. Significance of Studying the Sun

The study of the Sun holds immense importance due to its role as the primary source of energy that sustains life on Earth. Understanding the dynamics of the solar surface and its interactions with Earth's atmosphere is crucial for several reasons.

• Impact on Earth's Environment: Any changes occurring on the solar surface or its periphery can have significant implications for Earth's atmosphere. Solar activities such as powerful storms and flares can lead to disturbances in Earth's magnetosphere, affecting satellite-based operations, power grids, and navigational networks.
• Space Weather Concerns: Solar storms and flares can generate space weather events that pose risks to spacecraft, astronauts, and technological infrastructure in space. Studying the Sun helps in predicting and mitigating the potential impacts of such events on space missions and communications systems.
• Historical and Future Insights: Observatories like the Kodaikanal Solar Observatory (KoSO), with their long-term data collection efforts, provide valuable insights into the Sun's historical behaviour. This data not only helps in reconstructing the Sun's past activities but also facilitates the study of its behavioural changes over time. By understanding the patterns and cycles of solar activity, scientists can better predict future solar events and their potential impacts on Earth and space environments.
• Space Weather Forecasting: Research conducted on solar behaviour and its impact on space weather contributes to the development of forecasting models. These models are essential for issuing early warnings about potential solar disturbances, allowing for timely precautions and safeguards to be implemented.

• In a significant organisational shift, the Government of India segregated Astrophysics from the India Meteorological Department (IMD) in April 1971. This restructuring aimed to streamline and enhance the focus on astronomical research within the country.
• As part of this restructuring, the Kodaikanal Solar Observatory (KoSO) was brought under the umbrella of the Indian Institute of Astrophysics (IIA), based in Bengaluru, effective April 1, 1971. This integration marked a new phase in KoSO's journey, aligning it with a broader astrophysical research framework.

Digital Revolution and Data Repository

• Transition to Digital Data: Over its 125-year history, KoSO has transitioned from recording solar data on basic photographic plates or films to amassing a vast digital repository. This repository now contains an impressive 1.48 lakh digitised solar images, totalling 10 terabytes of data.
• Extensive Solar Image Collection: Among these digitized images are 33,500 white-light images showcasing sunspots, alongside numerous other images capturing the Sun's activity recorded daily since the early 20th century. KoSO's digital archive provides an invaluable resource for studying long-term solar behaviour and phenomena.

Advanced Instrumentation and Research Focus

Cutting-Edge Instruments

Today, KoSO boasts a range of advanced instruments designed for precise solar observations. These include

• H-alpha Telescope: Enables full disc imaging, providing detailed insights into solar phenomena.
• White Light Active Region Monitor (WARM): Equipped with calcium and sodium filters, facilitating simultaneous observations of the photosphere and chromosphere layers of the Sun.
• Solar Tunnel Telescope: Supports specialized observations and research initiatives focused on solar dynamics and features.

Continued Scientific Contributions

With its advanced instrumentation and rich data legacy, KoSO continues to contribute significantly to solar physics, space weather research, and broader astrophysical studies. Its high-resolution digitised images and comprehensive data coverage make it a unique and invaluable asset in the global astronomical community.

7. The Way Forward

By strategically focusing on the areas, KoSO can ensure its continued leadership in solar research for the next 125 years and beyond. Its dedication to scientific exploration and technological advancements will be instrumental in unravelling the mysteries of the Sun and its profound influence on our planet and the wider cosmos.