US to witness 1st total solar eclipse in 99 years: Here's all you must know

Stargazers in the US are in for a treat on Monday as the country is all set to witness the first total solar eclipse in 99 years.

The last such eclipse occurred in 1918 when the path of totality crossed both the Pacific and the Atlantic coasts of the US.

A total solar eclipse occurs when the sun is completely obscured by the moon. The moon's diameter appears to be the same size as that of the sun, blocking out its light.

On Monday in one-and-a-half hours 14 states from Oregon to South Carolina stretched across a 112-km-wide swath will experience night-like darkness for approximately two-and-a-half minutes in the middle of the day.

The eclipse enters the US from Lincoln City, Oregon, at 9.05 a.m. as a partial solar eclipse, becoming a total eclipse at 10.16 a.m., and will leave US shores at at 2.44 p.m. near Columbia, South Carolina.

The entire continent of North America will be treated to the solar eclipse.

"Anyone within the path of totality can see one of nature's most awe-inspiring sights... This path, where the moon will completely cover the sun and its tenuous atmosphere -- the corona. It will stretch from Salem in Oregon to Charleston in South Carolina," NASA said on its website.

"Observers outside this path will still see a partial solar eclipse where the moon covers part of the sun's disk," the statement added.

Taking advantage of the celestial event, US space agency NASA is funding 11 ground-based science investigations across the country to learn more about the sun and its effects on earth's upper atmosphere.

Six of these would focus on the sun's corona.

NASA has collaborated with student teams across the US to send balloons into the sky in one of the most unique and extensive eclipse observation campaigns ever attempted.

The eclipse would help expand the understanding about life beyond the earth.

NASA has also invited citizen scientist to participate in a nationwide science experiment by collecting cloud and air temperature data and reporting it via their phones during the eclipse.

The celestial event will be documented from NASA Armstrong Flight Research Centre in California from a unique vantage point at about 25,000 feet altitude.

NASA TV will also provide coverage of the eclipse. "The programme will feature views from jet aircraft, high-altitude balloons, satellites and specially modified telescopes.

"It will also include live reports from Salem, Oregon, Idaho Falls, Idaho, Beatrice, Nebraska, Jefferson City, Missouri, Carbondale, Illinois, Hopkinsville, Kentucky, Clarksville, Tennessee and at our home base at the College of Charleston (SC)," NASA TV said in a statement.