On Wednesday, January 31, 2018, the world witnessed a rare celestial event. For the first time in 152 years, a blue moon (a second full moon in a calendar month), a supermoon (when the moon is at its closest point to the earth) and a blood moon (a moment during an eclipse when the moon appears red because it is in the earth’s shadow) coincide on a total lunar eclipse day. (NASA) called this phenomenon the ‘Super Blue Blood Moon.’
It’s a visual treat. And those who are alive to witness this phenomenon are lucky, to say the least, for generations of humans have lived and died without having had the opportunity to witness such a rare celestial event.
The journey to understanding this celestial phenomenon started centuries ago by ancient Indian astronomers. The collection of classical Sanskrit literature on astronomy, written over a period of time by consecutive astronomers and mathematicians, displays a deep knowledge and understanding of the mean motion of the planets, the colours of the lunar eclipse, and the degree of their totality.
The Suryasiddhanta, for example, a Sanskrit treatise on Indian astronomy from the late 4th or the early 5th century BC, explains the differences in observing the lunar and the solar eclipse. “Owing to her clearness, even the twelfth part of the moon, when eclipsed, is observable; but, owing to his piercing brilliance, even three minutes of the sun, when eclipsed are not observable.” It also describes the changing colour of the moon in detail during the lunar eclipse:
arshadune sadhumram stat krsnamardhadhike bhavat
vimuncatah krsnatamram kapilam sakalagrahe // 6, 23//
‘When half (of the moon’s disk) has been taken away, (the colour) may be smoky; when more than a half, it is likely to grow black; when released (vimuncatah), dark-red; when the eclipse is total, brown) or reddish: kapila).’
The Aryabhatiya, a Sanskrit astronomical treatise, the only known surviving work of the legendary Indian mathematician, Aryabhata, omits the intermediate krsnatamra (which Al-Biruni describes as ‘dark-black mixing with red) and says:
paragrahanante dumrah khandagrahane sasi bhavati krsnah /
sarvagarse kapilassa krsnatamrastamomadhye // Gola 46.
“At the end of the eclipse – smoky, the moon is black when partly eclipsed; brown at totality, and dark-red in the midst of darkness.”
Bhaskara II, the Indian astronomer and mathematician, in his Grahanaganita, gave the first example of a differential coefficient and introduced the concept of tatkalika – the method of dividing the day into a large number of small intervals and comparing the position of the planet at small intervals – and gave colour codes for each of these intervals. As he wrote:
svalpe channe dhumravarnah sudhamsorardhe krsnah
krsnarakto’ dhike’ rdhat/
sarvacchanne varna uktah pisango
bhanoschanne arvada krona eva // Vol 2, v.36
“When very little is covered, smoke coloured; when half of the moon, black; black-red when more than half; when totally covered, the colour is called reddish brown.”
Similarly, VarahaMihira, the Indian astronomer and mathematician, in his well- known treatise Pancasiddhantika (The five astronomical canons), calculated the diametre of the shadow, duration of the eclipse, obscuration at any desired moment, and the time of total obscuration. In Chapter 6, he says:
sarvagrase pitam varnavisesam vadeeisanathe /
udayastagrasadhumram khandagrahane ca salilabham // 9 //
“At eclipse totality, the distinctive colour of the Ruler of the Night may be called saffron-yellow; smoky the beginning and the end; and inconstant when the eclipse is partial.
Ancient Indian astronomers did not simply call it the ‘Blood Moon.’ Instead, they distinguished between the red and the blood-red colour of the total lunar eclipse. This was well documented by scholars from across the world.
Al-Biruni, the Persian scholar and scientist who dedicated a considerable part of his life studying astronomy, and translating Sanskrit texts to Arabic and vice-versa, called the Indian astronomers and mathematicians, the ‘learned men supported by God’ (al-‘ulama’ al-mu’ayyadun min inda allah), and supported their views. As he wrote:
More correct is the view of the Hindus, viz. that the eclipse has the colour of smoke if it covers less than half the body of the moon; that it is coal-black if it completely covers one-half of her; that it has a colour between black and red if the eclipse covers more than half of her body; and, lastly, that it is yellow-brown if it covers the whole body of the moon.
In his compendium of astronomy – al-Qanun al-Masudi – an Encyclopaedia of Astronomical Sciences, known to be his greatest work, Al-Biruni dwells extensively on the colours of the lunar eclipse and ascribes this knowledge to the Indian astronomers. Here too, he praises the Indian astronomers for their accuracy, disagreeing with the Hellenistic astronomers.
The only colour the Indian Astronomers have not acknowledged is the colour green, one that is caused by the Ozone in the earth’s atmosphere.
Today, with varying methods of scientific documentation and measurement, science has evolved, and our understanding of such phenomenon has advanced. However, detailed accounts on the colours of the lunar eclipse, given by ancient Indian astronomers and mathematicians, have been relegated to the sidelines of history. Their accounts, written centuries ago, are neglected by most modern historians of science, partially for their inability to understand Sanskrit.
Instead, what is passed down across generations and what one hears in contemporary culture and popular media are mythological stories that perpetuate ignorance with a sense of awe and veneration. There is little wonder then that there are many who consider this celestial spectacle to be inauspicious, one that signals an impending doom.
If anything, this rare celestial phenomenon should be a reminder of the scientific observations and achievements made by ancient Indian astronomers and mathematicians, not one that perpetuates superstition.
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