Super 'blood moon' kicks off spooky season - here's how to see celestial event

A super harvest blood moon will light up the night sky Tuesday, just in time for spooky season.

The harvest full moon occurs every year in September, but this event will happen while the moon is at perigee, or its closest point to Earth. 

That means this harvest moon will be a supermoon, appearing up to 14 percent larger than a regular full moon. 

And in an extra-spooky twist, it will also be a blood moon. These only occur during a lunar eclipse and bathe the moon in red light. 

Like supermoons, blood moons occur a few times per year, but it's rare for these events to happen at the same time. 

This is the second of four consecutive supermoons that will grace the skies through November. 

It will be visible on the evening of Tuesday, September 17 and the morning of Wednesday, September 18.

For stargazers in the US, The super blood moon will rise out of the eastern sky at roughly 7:50pm on the East Coast and 7:10pm on the West Coast.

The lunar eclipse, which will make the moon appear tinted red, will take place Tuesday evening.

On the East Coast, it begins around 8:41 pm, reach its maximum at 10:44 pm and end by 12:47 am. 

On the West Coast, it will start at 7:12 pm, reach maximum at 10:44 pm and end by 12:47 am.

During the eclipse, you won't see the entire moon disappear behind Earth's shadow. Instead, you'll see a sliver of it vanish briefly before coming back into view.

That's because only that sliver will be obscured by the Earth's 'umbra,' or the darkest part of our planet's shadow.  

'Aside from the small darkened portion at the top of the moon's disk, most of the visible lunar disk will be in Earth's penumbra, the lighter portion of the planet's shadow that does not entirely block the sun's light,' astrophysicist Teresa Monsue of NASA's Goddard Space Flight Center told NPR.

But even this slight overlap between the moon and Earth's shadow is enough to change how we perceive the color of the lunar surface. 

During a lunar eclipse, the Earth passes between the sun and the moon. This partially blocks sunlight from reaching the lunar surface, but some light does slip through. 

Those photons have to pass through Earth's atmosphere to illuminate the moon. The atmosphere acts like a filter, scattering blue light away but allowing longer-wavelength red, yellow and orange light to pass.

This is what gives the moon the reddish-brown appearance that we refer to as a 'blood moon.'

Individually, a harvest moon, a supermoon and a blood moon are not especially rare or unusual events. They each happen every year. But it is rare to have all three phenomena appear in a single full moon.

The next time this will happen won't be until September 2033, and after that, it won't happen again until 2042.