Long term study of the sun using Kodaikanal and other digitized data archives
Kodaikanal Observatory (KSO) has archived more than 100 years of solar images in three different wavelengths namely white light, Ca K and H-alpha. These have been captured through telescopes with unchanged optics, which ensured uniformity in image quality for several cycles. Four sets of data consists of while light photoheliograms since 1904, the Ca-K line spectroheliograms since 1906, H-alpha spectroheliograms since 1912 to 1998 and K-pr prominences spectroheliograms since 1912 to 1998. The butterfly diagrams as produced from these different datasets reveal new trends and features to understand the irregularities of solar cycle behaviors. While combining these archive along with other data sources from digitized archives and recent space based data integrated time series have been produced, which are allowing us to generate pseudo magnetograms.
Prof. Dipankar Banerjee is currently the director of the Aryabhatta Research Institute of Observational Sciences (ARIES), Nainital, India. He is the co-chair of the Science working group of the “Aditya” mission. Aditya is the first dedicated Indian mission to study the Sun, expected to be launched by ISRO in 2023. He is also the project coordinator for the National Large-Solar Telescope Project (NLST). NLST is a proposed 2-meter ground-based telescope planned to be installed at a Himalayan site. He is also involved with NASA’s PUNCH mission. He is honorary fellow of the Indian Academy of Sciences and National Science Academy and currently the President of the Astronomical Society of India.