Chandra Grahan 2021: The partial eclipse will start at 12.48 pm and end at 4.17 pm (Representational)
The longest partial lunar eclipse in the past 580 years will occur on November 19 and will be visible from parts of Northeast India, an astrophysicist said on Saturday, noting that a similar lunar eclipse of such length won't reoccur for another 648 years.
The rare phenomenon will be visible from a few areas in Arunachal Pradesh and Assam, Director of Research and Academic at MP Birla Planetarium Debiprosad Duari told PTI.
The 2021 partial lunar eclipse will start at 12.48 pm and end at 4.17 pm, he said.
The duration of the eclipse will be 3 hours 28 minutes and 24 seconds, making it the longest in 580 years, Mr Duari said.
"A few areas in Arunachal Pradesh and Assam will experience the last fleeting moments of the partial eclipse just after the moonrise, very close to the eastern horizon," he explained.
The last time a partial lunar eclipse of such length occurred was on February 18, 1440, and the next time a similar phenomenon can be witnessed will be on February 8, 2669, he said.
The maximum partial eclipse will be visible at 2.34 pm as 97 per cent of the moon will be covered by the Earth's shadow.
The moon is likely to appear blood-red in colour, which happens when the red beams of the sunlight pass through the Earth's atmosphere and get least deflected and fall on the moon.
People in North America will be best placed to witness the entire event. All 50 US states and Mexico will be able to see it. It will also be visible in Australia, East Asia, Northern Europe, and the Pacific Ocean region.
The penumbral eclipse, which occurs when the sun, earth, and the moon are imperfectly aligned, will begin at 11.32 am and end at 5.33 pm, Mr Duari said.
The penumbral eclipse will be visible from UP, Bihar, Jharkhand, West Bengal and Odisha but it can be seen only briefly from these places, he said.
A penumbral eclipse is not as spectacular and dramatic as the partial eclipse and sometimes does not even get noticed, he said.
The last lunar eclipse was on July 27, 2018. The next lunar eclipse will be on May 16, 2022, but it will not be visible from India, Duari said.
The next lunar eclipse to be visible from India will be on November 8, 2022.