National Science Day is observed in Thailand every year on 18th August. This holiday celebrates the anniversary of a total solar eclipse in 1868 that was predicted by King Mongkut two years earlier.
King Mongkut or Rama IV was a King of Thailand and also one of the most revered monarchs of the country. Before he was a king he served monkhood where he studies astrology, astronomy, and mathematics. These developed his skills in astronomical measurement that helped him to change the official Buddhist calendar, that was miscalculated, that is why times for auspicious moments were incorrect.
Another achievement of his was the prediction of the solar eclipse, which would occur on 18th August 1868. In 1982 King Mongkut was proclaimed to be the Father of the science in Thailand and the annual celebration of National Science Day on 18th August.
The 50 Baht banknote issued in the year 2004 honors King Mongkut or Rama IV. The obverse of the banknote depicts Portrait of H.M. King Bhumibol Adulyadej (Rama IX), the reigning monarch, in the uniform of the Supreme Commander of the Armed Forces on the obverse. The reverse depicts Monument of H.M. King Mongkut (Rama IV) with globe and telescope along with Phra Pathom Chedi- world's largest Stupa.
Image Courtesy: banknotes.com