Skygazers are in for a celestial delight as the longest partial lunar eclipse of the century on Friday is likely to turn the moon to a red-brown hue, despite not being a blood Moon.
Lunar eclipses occur when the moon passes into the Earth's shadow. It the longest such eclipse in nearly 600 years but will be visible at to only those living in North and South America, Eastern Asia, Australia, and the Pacific Region, according to NASA.
The lunar eclipse began at 1.02 a.m. EST on Friday (11.32 a.m. IST) and will goes on till 7.04 a.m. EST (5.34 p.m. IST).
At 3.45 a.m. EST, more than 95 per cent of the Moon's disk will be in the umbra or the darker part of the shadow, and the Moon will appear red. The colour might be easier to see in binoculars or a telescope.
The eclipse will peak at 4.03 a.m. EST -- the best time to see the red colour.
By 4.20 a.m. EST, the redness will fade as less than 95 per cent of the Moon will be the Earth's umbra. It appears that a bite is taken out of the opposite side of the Moon from earlier.
"During a lunar eclipse, the moon turns red because the only sunlight reaching the moon passes through Earth's atmosphere," NASA said about the Beaver Moon eclipse.
"The more dust or clouds in Earth's atmosphere during the eclipse, the redder the moon will appear. It's as if all the world's sunrises and sunsets are projected onto the moon."
NASA said this partial eclipse is ultra-long because the moon is almost at the farthest part from the Earth in its orbit (known as apogee), which means the moon is moving a bit slower through the shadow of Earth.
Also, the fact the eclipse is almost total means "the moon spends a longer amount of time in the Earth's umbra than it would in a 'more-partial' eclipse", NASA stated.
"It's actually the longest partial lunar eclipse in a millennium, clocking in at three hours, 28 minutes and 23 seconds...and will remain the longest partial lunar eclipse for 648 years until February 8, 2669 (three hours, 30 minutes, and two seconds)."
There hasn't been a longer partial lunar eclipse since February 18, 1440 (three hours, 28 minutes, 46 seconds).
The next time a long total lunar eclipse will take place on November 8, 2022, the space agency said.