A total lunar eclipse, the first since December 2011, is set to take place with the Americas best placed to get a glimpse.
With a first phase - known as a penumbral eclipse - kicking off at 0453 GMT (1453 AEST) on Tuesday, the total lunar eclipse is due to start at 1706 AEST and last until 1824 AEST, the US space agency said.
The moon will fully emerge from the Earth's shadow at 2037 AEST.
While the entire event is visible from North and South America, sky watchers in northern and and eastern Europe, eastern Africa, the Middle East and Central Asia will be out of luck, according to NASA.
It's the the first of four consecutive phenomena of this kind this year and next, a series astronomers call a tetrad.
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The last time a tetrad took place was in 2003-2004, with the next predicted for 2032-2033. In total, the 21st century will see eight tetrads.
The year's second total lunar eclipse will take place on October 8, with the tetrad's remaining two expected on April 4 and September 28 of next year.
In some religious circles, this tetrad has particular significance since it coincides with important Jewish holidays - Passover this year and next, and the Feast of Tabernacles in October 2014 and September 2015.
For those eager to follow along from their computer screens, NASA will be transmitting real time images of Tuesday's eclipse, as well as scientific commentary, on its website.
