A lunar eclipse occurs when the moon passes directly behind the Earth and into its shadow. The lunar eclipse will also be visible in India, and this will be a "Blood Moon" as well, where the Earth's satellite takes on a reddish tinge.
A total lunar eclipse typically occurs once or twice a year and the next will take place on the night of January 21, 2019.
Dundonians will be well placed later this week to have a grandstand view of the longest lunar eclipse, or blood moon, of the century.
This will be a historical eclipse as it will last three hours and 55 minutes, making it the longest eclipse of this century. The eclipse will be noticeable from nations in Central Asia, Europe, Africa, South America, and Australia.
However the brightness of the red colour depends on how dirty the atmosphere is due to volcanic eruptions - and experts don't believe this particular blood moon will display a strong red.
On the evening of 27 July, we are waiting for a total lunar Eclipse.
When the white light from the Sun hits the Earth's atmosphere the blue colours in the white are scattered, meaning only the red colours will hit the moon giving it an eerie tint. Instead of light hitting the moon's surface, Earth's shadow falls on it.
Lunar eclipse on July 27: Timings for watching century’s longest eclipse in India
But why does the moon turn red? Underneath the moon to the right, Mars will be visible to the naked eye.
"This is what is called the first contact when the partial lunar eclipse begins", said the Hyderabad centre's statement. This will coincide with the time of long Eclipse. The last time Mars was bigger and brighter than this was in 2003, when it was less than 56 million kilometres away from Earth.
So if you are Brittany or Normandy don't get your hopes up.
The eclipse will reach maximum totality at 9.21pm and finish at 10.31pm, though the partial eclipse will continue for another two hours after that.
An opposition can occur anywhere in the planet's orbit and when it happens while Mars is at its closest to the sun, the event is known as perihelic opposition.