ST. LOUIS – Thursday has been another miserably hot day in St. Louis. Rain and storm chances this weekend will help burst our heat bubble. It looks like those showers will clear in time for skywatchers to see a total eclipse of the moon Sunday night.

Total eclipses of the moon happen during full moon when the sun, Earth, and moon are all aligned.

“The moon is moving into the Earth’s shadow, blocking out the light that would allow us to see it in the night sky,” said Will Snyder, the manager of the McDonnell Planetarium at the St. Louis Science Center. “And whenever that happens, it’s visible for practically half the Earth at once.”

The eclipse begins when the moon enters the faint outer portion of Earth’s shadow, the penumbra, but the most noticeable part will come when the moon begins to enter the umbra, Earth’s dark inner shadow. In St. Louis, that starts at 9:27 p.m. The moon will be completely in the umbra by 10:29 p.m. and the totality phase of the eclipse will last almost an hour and a half.

“You don’t have to stay up even past midnight if you don’t want to get to see the main event,” Snyder said. “And, compared to solar eclipses where there are lots of concerns about safety and wearing the special glasses, a lunar eclipse is just as easy as going outside and looking up.”

You’ll see the lunar eclipse called a blood moon. Why’s it called that? Though the moon is fully in Earth’s shadow, Earth’s atmosphere bends a bit of sunlight and indirectly lights up the moon’s surface.

“It almost acts like a prism in the Earth’s atmosphere, bending those red wavelengths of light, so that we can see that mudding red color. Hopefully, not too spooky and just something beautiful to look at,” Snyder said.

There will be another total lunar eclipse on Nov. 8, 2022, though the viewing for that one won’t be as good in St. Louis.

The planetarium is a great resource for anything going on in the heavens. Look for their weekly Night Sky Update on its website.