Blood moon: Get ready to watch century's longest lunar eclipse tonight

In India, the total Lunar Eclipse will be visible in Delhi, Pune, Bengaluru and Mumbai, among other cities

Friday will be a day to remember as the world is set to witness the rare celestial treat of the longest lunar eclipse to date. The total lunar eclipse will last for an hour and 43 minutes across Friday night and Saturday morning. The 21st century’s longest lunar eclipse, also called Chandra Grahan, is a cosmic phenomenon popularly referred to as ‘blood moon’. The vast majority of people on the Earth will be able to see this stellar show, which co-incides with Mars' closest approach to the Earth in over a decade.

A complete lunar eclipse will occur around the midnight of Friday and will last until the wee hours of the Saturday, with total duration of 1 hour 43 minutes. The longest total lunar eclipse of the last century happened on 16 July 2000, lasting nearly four minutes longer, at 1 hour and 46.4 minutes. We won’t get to see such a long lunar eclipse again until June 9, 2123, said a National Geographic report. 

Total lunar eclipse timings in India

In India, the eclipse will commence around 11:54 p.m. on 27 July, total eclipse would begin at 1 am on July 28 and end at 2:43 a.m. Viewers in India, especially astronomy enthusiasts, are lucky since the record-setting eclipse, both partial and the total, will be entirely visible from most parts of the country, said PTI reports.

Where you can see it in India

Total lunar eclipse will be visible across several cities including Delhi, Pune, Bengaluru and Mumbai, reported NDTV.

But it will not be visible in North America and Antarctica. People in Asia, Middle East and Africa will have the best view of the eclipse and those in Europe, South America and Australia will see partial views.

Here is everything you need to know about this rare cosmic phenomenon of the 21st century:

What is a lunar eclipse?

A lunar eclipse occurs when the sun, the Earth and the Moon are perfectly aligned or when the Earth comes in between the Sun and the Moon and covers the Moon with its shadow. The Moon passes directly behind Earth and into its shadow and a lunar eclipse can occur only on the night of a full moon or Poornima day. During a total lunar eclipse, the Earth completely blocks direct sunlight from reaching the Moon. During the eclipse, the moon will be at its most distant point from Earth in its month-long orbit—known as ‘apogee’. The apogee moon will make the lunar eclipse appear 13 per cent smaller than average. As a result, it will take the moon or Earth’s natural satellite more time to cross Earth’s shadow, making the eclipse last longer, reported the Guardian.

What is a blood moon?

A total lunar eclipse and a blood moon are essentially the same thing with slightly different meanings. A 'blood moon' is a colloquial term for a lunar eclipse. A blood moon is caused by an effect known as Rayleigh scattering; this happens when moon is in total shadow during the total eclipse, some light from the sun passes through the Earth's atmosphere and is bent toward the moon. Typically, the moon reflects the sun’s light, but during an eclipse, the moon’s orbit takes the light through the Earth’s shadow. And the light that reaches the moon is tinged with a reddish hue colour. The only light that can be seen is refracted through the earth's shadow, and this light looks red just like with the sunset. This is why the astronomical event is often called a ‘blood moon’.

Moreover, lunar eclipses are less common than solar eclipses. This eclipse is rare because it will last for so long and the moon will be ducked in the Earth’s shadow for four hours and totally eclipsed for one hour and 45 minutes.

Tips to watch the ‘blood moon’

The blood moon eclipse is completely safe to look at without any special equipment. You need not buy a pair of binoculars because the eclipse will be visible to the naked eyes.

In big or metropolitan cities, light pollution and cloud cover at night could be a few of the hindering factors.