(Radio Iowa) – Forecasters say much of Iowa should have mostly clear skies tonight (Thursday), allowing a good view of what promises to be the longest partial lunar eclipse in centuries. Professor Siobahn Morgan, who heads the Astronomy Department at the University of Northern Iowa, says the full moon will be almost completely covered by the shadow of the Earth, causing what’s called a Blood Moon.

“It will mainly turn red. The part of it that will not be eclipsed, of course, will be kind of muted and grayish color or dimmed out, not as colorful as most of the moon,” Morgan says. “It would be very cool to see, especially with binoculars.” The Earth’s shadow should start covering the moon around 1:18 A-M and will eventually darken about 98-percent of our natural satellite’s surface.

A blood moon should be visible tonight & early Friday morning.

“The lunar eclipse duration, when it first starts to enter the outer shadow of the Earth and then leave it is about three-and-a-half hours,” Morgan says. “The fuller, darker part of the eclipse is much less duration.” Given the position of the Earth and moon, the experts say this will be the longest-lasting partial lunar eclipse since the year 1440, while there won’t be a longer similar event until 2669. That’s reason enough to set the alarm, bundle up, go outside and take a gander, right?

“The peak of the eclipse happens just a little bit after 3 AM,” Morgan says. “Anytime between about 2 AM and 4 AM would give you an interesting view. The closest you are to 3 AM, the better.” In addition to the full moon, the partial lunar eclipse and the Blood Moon, tonight’s glowing orb in the sky is also referred to as a Beaver Moon — the first full moon in November. The origins of the name are thought to come from Native Americans who set traps for beavers during this month prior to the freezing of rivers and streams to guarantee a good supply of winter furs.