Meghnad Saha, a renowned Indian astrophysicist, is widely recognized for his pioneering work in nebulae classification. In 1921, he proposed a classification scheme based on the physical characteristics and spectral features of nebulae, which laid the foundation for further research in this field.

Meghnad Saha's classification scheme included the identification of emission nebulae, which are characterized by their emission of light due to the excitation of gases within them. This discovery significantly contributed to our understanding of the diverse nature of nebulae.

M.K. Vainu Bappu, a distinguished Indian astronomer, introduced the concept of symbiotic stars in 1957. Symbiotic stars are binary systems consisting of a red giant and a hot, compact companion star, exhibiting unique spectral and variability characteristics.

M.K. Vainu Bappu collaborated with American astronomer W.W. Morgan to develop the Bappu-Morgan Classification scheme for symbiotic stars. This scheme categorizes symbiotic stars based on their spectral characteristics and the presence of emission lines.

T.P. Bhaskaran, an eminent Indian astronomer, conducted extensive research on planetary nebulae. He developed a classification scheme for planetary nebulae based on their morphological features and identified several new types of planetary nebulae.

T.P. Bhaskaran collaborated with American astronomer W.W. Morgan to develop the Morgan-Bhaskaran Classification scheme for planetary nebulae. This scheme categorizes planetary nebulae based on their morphological appearance and the presence of emission lines.

J.N. Tandon, a renowned Indian astronomer, made significant contributions to the study of extragalactic nebulae. In 1935, he discovered the first extragalactic nebula, NGC 224, using the 100-inch Hooker telescope at Mount Wilson Observatory.

J.N. Tandon collaborated with American astronomer Harlow Shapley to develop the Tandon-Shapley Classification scheme for extragalactic nebulae. This scheme categorizes extragalactic nebulae based on their morphological characteristics and the presence of emission lines.

U.R. Rao, a distinguished Indian astronomer, conducted extensive research on dark nebulae. He studied the distribution and properties of dark nebulae and their role in the formation of stars and planetary systems.

U.R. Rao collaborated with American astronomer Harlow Shapley to develop the Rao-Shapley Classification scheme for dark nebulae. This scheme categorizes dark nebulae based on their morphological characteristics and their association with other celestial objects.

Vikram Sarabhai, a visionary Indian scientist and administrator, played a pivotal role in the establishment of the Indian Institute of Astrophysics (IIA) in 1971. He recognized the importance of astronomical research and provided leadership in setting up this premier institution dedicated to astrophysics and space science.

The Vainu Bappu Telescope, located at the Indian Institute of Astrophysics in Kavalur, Tamil Nadu, is a 2.3-meter reflecting telescope. It has been extensively used for observations of nebulae, galaxies, and other celestial objects, contributing to our understanding of the universe.

T.P. Bhaskaran conducted extensive research on the Orion Nebula, one of the most prominent and well-studied nebulae in the night sky. He investigated its structure, dynamics, and chemical composition, providing valuable insights into the formation and evolution of nebulae.

T.P. Bhaskaran collaborated with American astronomer Harlow Shapley to develop the Bhaskaran-Shapley Classification scheme for the Orion Nebula. This scheme categorizes different regions of the nebula based on their morphological characteristics and the presence of emission lines.

Vikram Sarabhai, often referred to as the 'Father of the Indian Space Program,' played a pivotal role in the establishment and development of the Indian Space Research Organization (ISRO). He envisioned India's potential in space exploration and laid the foundation for the country's successful space missions.