If you look outside on September 27th, 2015,
you can catch a glimpse of a very rare event in the night sky:
a supermoon lunar eclipse.
To understand what this is – first, take a full moon.
Now add the closest approach the moon makes to the Earth on its elliptical orbit –
which results in it looking up to fourteen percent larger in diameter.
That's a supermoon.
Now combine this with a lunar eclipse,
when the Moon passes directly behind the Earth into its shadow - giving it a red tint.
Now you have a supermoon lunar eclipse.
This is a really special event, because it doesn't happen very often.
Let's take a look back.
Since 1900, a supermoon lunar eclipse has only happened 5 times.
A lot changes here on Earth in between these moments.
In fact, the last time you could see this event was 1982.
And if you miss seeing it in 2015, your next opportunity won't come until 2033.
So mark your calendar and head outside on September 27th.