On Sunday, there will be a total eclipse of the harvest moon. It’s the last lunar eclipse we’ll see for another four years. The Kalamazoo Astronomical Society will be hosting a public watch party Sunday night at 8 p.m. at Richland Township Park.
As always with lunar eclipses, Richard Bell and Mike Sinclair of the astronomical society say there's no need for protective eye gear - since you won't be staring into the sun.
What's a Harvest Moon?
A harvest moon is a full moon closest to the autumnal equinox, which is in late September. Richard Bell says it's a bright moon that's visible all night long. He says this often gave farmers enough light to harvest their crops long into the night.
The harvest moon is often an orange or red color. Mike Sinclair says that's because of the refraction of sunlight through the Earth's atmosphere:
"To some extent you could argue or you could say that the atmosphere of the Earth is like a magnifying glass. It kind of bends light around a little bit because of refraction. Light hits the atmosphere, bends a little bit - when it comes out it bends again. And when you've got the shadow of the Earth itself centered over the moon, any residual light from refraction then is observed reflecting off the moon and it gives it this really distinctive kind of copper color or blood red."
Bell puts it this way:
"Kind of a more colorful way to say it is that the orangey color of the moon is caused by all the sunsets and sunrises that ring around the Earth at that time," he says.
Five Hours of Eclipse Viewing
Sinclair says this is one of the longer lunar eclipses. From the time that the moon hits the edge of the Earth's shadow (the penumbra) to the end of the shadow, is about five hours.
Richard Bell gave us a quick forecast. These times are approximate.
8:12 p.m. The moon hits the edge of the Earth's shadow. You probably won't see anything yet.
8:50 p.m. You might notice some darkening on the moon.
9:07 p.m. Moon begins to move into the darkest part of Earth's shadow, also known as the umbra.
10:11 p.m. The moon will be totally eclipsed by Earth's shadow.
"Super Moons"
This harvest moon will be what's often called a "super moon," though Bell and Sinclair say it won't be as big as that name implies. A more accurate name for these moons would be "perigee moons." A perigee moon is when the moon is the closest to Earth in it's orbit. But Sinclair says the moon is almost the same distance from Earth all the way around, so it's not that striking of a change.
"The difference between the closest approach to the moon, perigee, and its greatest distance, apogee, is really not that dramatic. And it's really hard to actually see the difference," he says.
Other Upcoming Eclipses
There will be a total solar eclipse across the continental United States in 2017. Bell says it's going to be a big one.
The next lunar eclipse will not be until January 2019 and Bell says we'll likely miss it here in Michigan because of cloud cover that time of year.
