Here's when you can see the longest lunar eclipse in the 21st century, based on where you live

On the night of July 27 and the early morning hours of July 28, sky-watchers in the Eastern Hemisphere will be treated to the longest lunar eclipse of the 21st century.

Astronomers expect the total eclipse to last for an hour and 43 minutes, with the entire event, including the partial eclipse, lasting 3 hours and 55 minutes.

A lunareclipse occurs when the sun, Earth, and moon are aligned, and the moon's orbitbrings it directly into Earth's shadow . Earth's shadow, known as the umbra, gives the moon a reddish "blood moon" color due to the way the Earth's atmosphere refracts the sun's light.

The total eclipse will only be visible to parts of Africa, the Middle East, Russia, and India, while some of the regions to the east and west will be able to see a partial eclipse. The eclipse won't be visible to viewers in the US and Canada, but you can watch the eclipse live on July 27.

This map shows who will get to see the event. All of the countries in the dark red area in center will get to see the entire eclipse event, from start to finish. Moving eastward or westward, those areas will see less and less of the total, partial, and penumbral eclipse.

Map of the June 27-28 eclipse.Screenshot/ Timeanddate.com

The eclipse will begin at 7:30 p.m. UTC, or Coordinated Universal Time, and end at 9:13 p.m. UTC. The peak of the total eclipse will occur at 8:22 p.m. UTC.

UTC is the most precise time kept by atomic clocks around the world, and is frequently used by scientists. To convert UTC to your local time zone, EarthSky offers a handy guide . That'll tell you exactly when to look up to check out the eclipse. If you prefer to avoid doing any math, you can also enter in your city here .

Here's when to look up at the night sky to see the maximum eclipse by major city

Full eclipse:

Cairo, Egypt : 10:21 P.M. (Eastern European Time)

Cape Town, South Africa : 10:21 P.M. (South Africa Standard Time)

Addis Ababa, Ethiopia : 11:21 P.M. (Eastern Africa Time)

Dar es Salaam, Tanzania : 11:21 P.M. (Eastern Africa Time)

Jerusalem, Palestine: 11:21 P.M. (Israel Daylight Time)

Dubai, United Arab Emirates: 12:21 A.M. (Gulf Standard Time)

Karachi, Pakistan: 1:21 A.M. (Pakistan Standard Time)

Mumbai, India: 1:51 A.M. (India Standard Time)

Partial eclipse (from East to West):

London, United Kingdom : 9:21 P.M. (British Summer Time)

Marrakesh, Morocco : 9:21 P.M. (Western European Summer Time)

Berlin, Germany : 10:21 P.M. (Central European Summer Time)

Athens, Greece : 11:21 P.M. (Eastern European Summer Time)

Bangkok, Thailand : 3:21 A.M. (Indochina Time)

Shanghai, China : 4:21 A.M. (China Standard Time)

Tokyo, Japan : 4:42 A.M. (Japan Standard Time)

Sydney, Australia : 6:21 A.M. (Australian Eastern Standard Time)

Auckland, New Zealand : 7:22 A.M. (New Zealand Standard Time)