Chandra Grahan or Lunar Eclipse 2018: All you need to know

Get ready for a celestial double feature unlike anything seen in decades: Mars is about to make its closest approach to Earth in 15 years-just as the full moon blushes red in the longest "blood moon" eclipse of the century.

Why is it called a Blood Moon?

A lunar eclipse occurs when the Moon falls under the Earth's shadow by passing directly behind the Earth. This day will also be a Blood Moon, where the earth's satellite takes on a reddish colour.

During lunar eclipse or Chandra Grahan, the earth tends to block direct sunlight reaching the moon. The only light that reflects is refracted by the earth's atmosphere; this light appears red in colour, which is why it is called Blood Moon.

How rare is it?

If this eclipse is rare, it is because it will last for so long. The moon will be in the Earth's shadow for four hours and totally eclipsed for one hour and 43 minutes, which is just short of the theoretical limit of a lunar eclipse (one hour and 47 minutes). The eclipse will last for so long on Friday night because the moon will be passing through the centre of the Earth's shadow.

When to watch

In India, it will be seen in Delhi, Mumbai, Bengaluru, Chennai, among other major cities from 11:44 pm IST, and the first phase is expected to set in from 11.54 pm IST and the entire eclipse from 1.00 am IST on July 28. The second phase of the eclipse will start from 2:43 am IST, wherein a partial lunar eclipse will be taking place.

Superstitions related to eclipses

Superstitions have been long associated with the lunar eclipse since time immemorial and it was widely believed that our mind and body go through some changes during the eclipse. Here's a list of rituals that have been long followed by people:

• Avoid eating cooked food - The popular belief is that during the eclipse, the food that you consume would not get digested properly.

• People say one should avoid travelling during the eclipse.

Pregnant women are asked to stay indoors too. Although there isn't any scientific reason behind these, it has been firmly engraved in our culture that the rays, which are more powerful during the eclipse, can affect the baby inside the womb.

• Avoid sexual intercourse during the eclipse. As the saying goes, sex during an eclipse could produce demon-children and might bring turmoil in life.

• Other rituals include cleansing the home with incense sticks or crystals and meditating. Some people even consider this as a good opportunity to cleanse themselves from all sins and let go of their negative past during the eclipse as the Moon appears bright and fresh at the end of the eclipse.