On Monday, the United States of America will witness a rare phenomenon in its skies, a total solar eclipse which will cast a shadow cutting diagonally through the American mainland.

The eclipse will pass through Oregon to Charleston, South Carolina. Meanwhile, many areas of Canada, Central America and the northern part of south America will experience a partial eclipse.

The August 21 eclipse is occurring after a gap of 99 years, the previous astronomical phenomenon was recorded way back in the US in 1918.

While Americans have begun gathering in large numbers at campsites around the city of Oregon to witness the once in a lifetime natural occurrence, India will not be able to get a first-hand experience of the total eclipse on Monday and will have to wait till 2034.

Not in the US? Here is how to watch it  NASA has, however, planned to live stream the eclipse to the rest of the world. According to the NASA website, “Viewers will be provided with a wealth of images captured before, during, and after the eclipse by 11 spacecrafts, at least three NASA aircraft, more than 50 high-altitude balloons, and the astronauts aboard the International Space Station.” Many news channels will also broadcast the eclipse live.

Termed as ‘The Great American Eclipse’, the partial phase of the eclipse will begin over the Pacific Ocean at 1546 GMT (9.16 PM IST) and will end at 18.48 GMT (12.52 AM IST). In totality it will cross from Oregon into Idaho, Wyoming, Nebraska, Kansas, Missouri, Illinois, Kentucky, Tennessee, Georgia, North Carolina and, finally, South Carolina, also passing over tiny slivers of Montana and Iowa. The eclipse will last longest near Carbondale, Illinois for 2.44 minutes.

The different phases of the total solar eclipse

According to NASA, in the initial phase of the total eclipse, the Sun’s disk will be partially blocked by the moon which can last for over an hour and can be viewed by a pair of specially designed glasses. In phase two of the rare eclipse, sunlight streaming through the Moon’s valleys will create a bright flash of light, giving the appearance of a diamond ring. This marks the final moments before totality takes over.

Phase three is refereed as the Baily’s Beads where only low lying valleys on the moon’s edge will allow shimmering light to pass through, leading to the complete solar eclipse in phase four, which lasts for under a minute in some of the locations. In the final stages, crescent will begin to peek from behind the moon. Experts have advised people to not look directly at the Sun during the eclipse and especially in the final phase which may render severe damage to eyes.

Monday’s total solar eclipse comes after 1979 when the US mainland experienced the last eclipse across Oregon, Washington state, Idaho, Montana and North Dakota, entering into Canada.

However, if you give it a miss on Monday, the next total solar eclipse will be in 2019 over Argentina, South Pacific and Chile. America will experience the next total solar eclipse passing  through its mainland only in April 2024 when the totality will cross from Texas, through the Midwest, Indianapolis, Cleveland, New York, up over New England and out over Maine and New Brunswick, Canada.