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Superstitious stargazers and anyone who enjoys staring at the moon are in for a treat this week.

Get ready for the harvest moon effect — when it will seem like five consecutive nights of full moons.

And for the first time in 19 years, folks in Wisconsin will get a full moon on Friday the 13th.

Because of the tilt of the Earth, the path of the moon through the night sky will be as close to the horizon as it gets all year, moving more horizontally and rising sooner than normal each night. On average the moon rises around 50 minutes later each night than the night before, but near the fall equinox, the moon rises less than 30 minutes later from night to night.

Since a quick glance at the moon a day or two before and after appears as if it's full, Wednesday through Sunday will seem like a bright, glowing parade of full moons, said Bob Bonadurer, director of the Milwaukee Public Museum's Daniel M. Soref National Geographic Dome Theater & Planetarium.

"It's more of that effect of five full moons in a row that results from the moon rising more quickly than usual. It just feels and looks like five full moons in a row," said Bonadurer.

The full moon closest to the first day of autumn, Sept. 23 this year, is called the harvest moon. It got its name because farmers were able to stay out in their fields longer to harvest their crops under a full moon.

Look toward the east sky this week to glimpse Earth's celestial neighbor. Moonrise on Thursday is 6:54 p.m. in southeastern Wisconsin, 7:20 p.m. on Friday and 7:44 p.m. Saturday.

"This is the time of year when it's still nice out but the sun is setting earlier and people are noticing the moon more. I think that's why the harvest moon remains popular," Bonadurer said.

The forecast calls for partly cloudy skies Friday night but mostly clear skies Saturday and Sunday nights, according to the National Weather Service. 

For people who associate bad luck with Friday the 13th, it's rare for a full moon to fall on that superstitious day. This month people in the Eastern Time Zone won't get a full moon until early Saturday, Sept. 14. But a full moon will occur for the rest of the United States on the 13th.

In Milwaukee, the full moon occurs at 11:32 p.m.

The last time a full moon occurred on Friday the 13th was in June 2014, but only in the Eastern Time Zone. And the last time for a full moon to occur for the entire country on Friday the 13th was October 2000.

It won't happen again until Aug. 13, 2049, according to the Farmers' Almanac, which figured a "Friday the 13th full moon" happens on average once every two decades.

One other noteworthy thing about this month's full moon — it will be a mini-moon.

Remember the super moon in January and February? It was called a super moon since it appeared 7% larger than normal because the moon, which travels on an elliptical orbit, was closest to the Earth. 

This month the full moon nearly coincides with the apogee, the point in its orbit when it's at its greatest distance from Earth, roughly 252,000 miles away. The super moon was 30,000 miles closer to our planet.

So the micro moon will appear 14% smaller than a super moon, and 7% smaller than a normal moon.

However, to human eyes, it will look like the same old moon.

"It's not noticeable, even if you study it," said Bonadurer.

The Milwaukee Public Museum is offering an astronomy class for adults in the Daniel M. Soref National Geographic Dome Theater & Planetarium for five weeks on Wednesday nights starting Oct. 2. For more information:


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