The full moon on the night of Friday (July 27) , will present the longest total lunar eclipse of the 21st century (2001 to 2100). The total phase of the eclipse – called the totality – spans 1 hour 42 minutes and 57 seconds.
A partial eclipse precedes and follows the total phase of the eclipse, each time lasting 1 hour and 6 minutes. So, from start to the finish on July 27-28, 2018, the moon spends nearly 4 hours (3 hours and 55 minutes) crossing the Earth's dark umbral.
The eclipse is estimated to start in India at 11:44pm IST on Friday night and the total lunar eclipse 2018 is expected to begin at 1am IST. From 1:15am to 2:43am, the moon will be in the middle of the Earth's shadow and will appear reddish in colour. The eclipse will continue till 4:58am though the effect will not look as great.
During the long total phase of the July 27 lunar eclipse – the totality – the moon will turn red from sunlight filtering through Earth's atmosphere onto the moon's surface. And Mars will be near the moon, exceptionally bright – brighter than since 2003.
On Friday, the sun, Earth and moon are aligned – placing the moon opposite the sun in our sky – producing an eclipse as Earth's shadow falls on the moon's face. On the same night, the sun, Earth and Mars are also aligned, bringing Mars also opposite the sun in sky, just like the full moon.
This lunar eclipse is primarily visible from the world's Eastern Hemisphere (Europe, Africa, Asia, Australia and New Zealand). South America, at least in part, can watch the final stages of the eclipse just after sunset July 27, whereas New Zealand will catch the beginning stages of the eclipse before sunrise July 28.
According to NASA ,the next total lunar eclipse visible from North America will occur on January 21, 2019. Totality on that day will last 1 hour and 2 minutes.