125 Years of Kodaikanal Solar Observatory (KSO)

Context

Kodaikanal Solar Observatory recently completed 125th years.

Origin of Kodaikanal Solar Observatory (KSO)

• Establishment of Madras Observatory by the British: 

  • In 1792, the British East India Company established the Madras Observatory, a first of its kind in this part of the world.
    • The starting apparatus consisted of two three-inch achromatic telescopes, two astronomical clocks with compound pendulums, and a transit instrument. 
    • Its first capture of a solar eclipse on August 18, 1868 created the subject of solar physics. 
    • The spectroscope was used for the first time to discover the gaseous nature of solar prominences.

• Establishment of Kavalur Observatory: 

  • In 1968 a new field observatory was started at Kavalur, Tamil Nadu for stellar spectroscopy and photometry. 
    • Most of the observations for research on galaxies, stars and the solar system are now obtained from Kavalur.
    • The Kodaikanal Solar Observatory is now spread over numerous buildings and telescopes. It uses a combination of hand-drawn images, photographic plates and films to record its solar observations. 
    • There are approximately 200,000 glass plates in the archives and four telescopes: 
      • H-alpha telescope
      • Twin telescopes 
      • White light Active Region Monitor (WARM) telescope.
    • Its full range of equipment also includes a spectrograph, a photoheliograph, two full-disc spectroheliograph and a radio spectrograph.

Contributions of Kodaikanal Solar Observatory (KSO)

• Confirming Evershed effect: TheKodaikanal Solar Observatory (KSO) was the first to confirm the Evershed effect in 1909—the radial motion in sunspots.
• Data Repository: The KoSO has been imaging the Sun for over a century now, and has a rich repository of data. 
  • This is extremely useful not only to reconstruct the Sun’s historic past but also to link its behavioral changes to better understand and predict its future and its impact on life on Earth and Space weather.
• Solar Observation: It observes and records the Sun and its characteristics, including daily white light photography of the solar disc from the time it was set up.
  • Only two other institutions—the Meudon Observatory in Paris and the Mount Wilson Observatory—have a collection that spans an equivalent time period.
• Monitoring Equatorial Electrojet: Due to its location in the Palani Hills of southern India, the KSO plays a central role in observing changes to the equatorial electrojet, an electric current which travels in the Earth’s ionosphere. 
• Public Outreach: The Kodaikanal Solar Observatory is engaged in public outreach through workshops and educational initiatives.

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