Fifty years to the day since mankind launched the first mission to set foot on it, the Moon is set to treat Earthlings to a partial lunar eclipse on Tuesday (in select countries, Wednesday in others). More than 400,000 people worked on NASA's Apollo 11 mission, which launched on July 16, 1969 and put the first humans on the Moon four days later. Britain's Royal Astronomical Society said in a statement the event would be visible from parts of northern Europe, Asia, Africa, South America and Western Australia. Lunar eclipses happen when the Earth gets aligned in between the Sun and the Moon.
Sky enthusiasts in India will also be to witness a three-hour long partial lunar eclipse early Wednesday. The eclipse will begin for the Indian stargazers around 1.31 am on Wednesday, the research and academic director of M P Birla Planetarium in the city, Debiprosad Duari, told PTI. The greatest partial eclipse when the Moon will look the darkest will be around 3 am.
"Skywatchers should not miss this chance since there will be no proper lunar eclipse till 2021," he said.
The Moon will remain partially eclipsed till 4:29am on Wednesday. So it is a golden opportunity for the sky enthusiasts in the country as the eclipse will be visible almost throughout the night, he said.
On Tuesday night, only a part of the Moon will pass the Earth's shadow. Around 3:01am on Wednesday, 65 percent of the Moon's diameter will be under the shadow of the Earth, Duari said.
Elaborating on the celestial phenomenon, he said it takes place only at full Moon night, when it, the Sun and the Earth are in a perfect straight line. As the Sun's rays fall on the Earth, its shadow falls on to a patch of space. When the Moon enters the patch of shadow there is lunar eclipse.
The patch of shadow is actually composed of two cone-shaped parts - one nestled inside the other. The outer shadow or penumbra is a zone where the Earth shadow is partial and blocks some, but not all of the Sun's rays. In contrast, the inner shadow or umbra is a region where the Earth blocks all direct sunlight from reaching the Moon. When only a part of the Moon passes through the umbra, a partial lunar eclipse is seen. If the entire Moon passes through the umbral shadow, then a total eclipse of the Moon occurs, he said.
India will witness the next lunar eclipse on May 26, 2021, when it will be a total one, he added. When asked, he said lunar eclipses are completely safe to view with the naked eye. One does not need a telescope to watch the lunar eclipse although a good pair of binoculars will enhance the experience, Duari said.
Written with inputs from agencies