Kodaikanal Solar Observatory, Solar observatory in Kodaikanal, India

Kodaikanal Solar Observatory stands on the southern tip of the Palani Hills, 4 km from Kodaikanal town. Its cluster of pale yellow buildings with red-tiled roofs includes a central rectangular block with a hipped roof, a gabled entrance porch with an open white door, and two silver-grey domes with dark horizontal seams. A 12 m solar tower with a modern spectrograph was added in 1960, and a 60 cm coelostat on an 11 m tower feeds a 60 m underground tunnel telescope.

In 1881 Blanford, Meteorological Reporter to the Government of India, urged improved solar observations; in May 1882 Madras government astronomer Norman Robert Pogson proposed photographing and spectrographing the sun with a 20-inch telescope at a South Indian hill station. After a famine in the Madras Presidency, a committee chaired by Lord Kelvin decided on 20 July 1893 to build a solar physics observatory at Kodaikanal for its southern, dust-free, high-altitude site, with Michie Smith as superintendent. Equipment moved from the Madras Observatory from 1895, the observatory was founded on 1 April 1899, and first observations began in 1901.

The observatory runs public astronomy outreach: guided tours of the facility, access to its astronomy library, night-time telescopic sky viewing, and university-level courses, seminars and workshops. The 20 cm refractor, acquired in 1850 and remodelled in 1898, is sometimes made available to visitors for night-sky viewing.

The observatory sits on the southern tip of the Palani Hills, 4 km from Kodaikanal town, and is reached by road from the town. Public tours of the facility, the astronomy library and night-sky viewing through the 20 cm refractor are offered; the white-light solar pictures are taken on roughly 200 days a year, sky permitting.

The observatory holds India's oldest continuous records of solar data, documenting decades of scientific observation. These valuable records help researchers track and understand long-term changes in solar activity.