Total Lunar Eclipse Party!

This Sunday, September 27, there will be a total eclipse of the Moon! What's more, this full moon happens when the Moon is at perigee, meaning it is a bit closer to the Earth than usual, causing it to look a bit larger. The Moon at perigee is sometimes called a supermoon (more on that below). The Peoria Astronomical Society, Peoria Riverfront Museum, Peoria Park District, and Peoria Public Library are teaming up to host a viewing party! Join us this Sunday at Donovan Park for this FREE event!

The totally eclipsed Moon will look orange-red. Image Credit: Wikipedia Commons

So what's so super about this full moon? 

The Moon does not orbit the Earth in a perfect circle. Because its orbit is just slightly elliptical, or egg-shaped, sometimes the Moon is closer to the Earth than usual, and sometimes it is farther away. Astronomers say the Moon is at perigee when it is at its closest point in its orbit, and apogee when it is at its farthest point. Since those words don't mean much to non-astronomers, and don't sound very interesting, sometimes the full moon at perigee is referred to as a supermoon, and sometimes the apogee Moon is referred to as a minimoon. 

Notice the apparent size difference of the supermoon at the top right. Image Credit Brian Koberlein. Follow his blog for an excellent daily dose of science!

What is happening during a lunar eclipse?
Well, as the Sun shines on Earth, the planet casts a shadow into space. And as the Moon makes its way around Earth every month, it usually passes a little above or below the shadow. But every once in a while, it passes right through Earth’s shadow, and we get a lunar eclipse.

Sunday’s eclipse will start 8:07 PM. Over the course of an hour, you’ll see Earth’s shadow gradually creep across the face of the Moon, giving it an odd appearance – sort of like a phase of the Moon, but not quite. When the Moon is totally eclipsed, from 9:11-10:23 PM, you will see the full Moon, but with an orange-red color. The eclipse ends at 11:27 PM. 

Image Credit: National Air and Space Museum
Image is not to scale.

Why can you still see the Moon when it is completely in Earth’s shadow? A little bit of sunlight passes though the atmosphere, bending around Earth and into Earth’s shadow. As the Moon passes through Earth’s shadow, that red light reflects off the Moon’s surface. A nice way to think of it is the sunrises and sunsets happening all over Earth are being cast onto the Moon. The red color is why some people are calling the eclipse a “Blood Moon”. A lunar eclipse is a really pretty (and slightly eerie) sight to see.

So what's going on with this party?  
Peoria Astronomical Society, Peoria Riverfront Museum, Peoria Public Library and the Peoria Park District are hosting a Supermoon Eclipse Party, with all events free and open to the public on Sunday September 27 in Donovan Park. You can come as early as 6 PM if you want to watch the moonrise at 6:47, and kids can participate in a few activities put on by the Library until dark. After dark, members of the Astronomical Society will have telescopes out for viewing, and the big telescope in the observatory will be open. Planetarium staff will be on hand to help answer your questions and point out some constellations with our green lasers. You might want to bring chairs or blankets, flashlights, bug spray, and some snacks. 

If it is cloudy and you can't see the Moon, we won't be able to have the party. We will put a link on the Museum's website with a live stream of the eclipse. 

We hope to see you there!