Chicago sky-watchers could be treated to a dazzling celestial display Sunday night as the sun, moon and Earth align for the first total lunar eclipse in more than three years.
Weather permitting, the entirety of North and South America will be able to witness the Earth cast its shadow upon the moon. Starting at 9:34 p.m. Central time, a dark, curved shade will become visible on the face of the moon, according to Michelle Nichols, director of public observing at the Adler Planetarium.
“It’s going to look like someone took a bite out of the moon, but what you’re actually seeing is the earth’s shadow,” Nichols said. “People ask me all the time, what’s your favorite thing about lunar eclipses? I tell them, look at the shape of the shadow — it’s curved. You can see the curvature of the earth. Ancient Greeks and others knew the Earth was round because of its shape on the shadow of the moon.”
By 10:41 p.m., Nichols says, the moon will be completely within the fully shaded region known as the umbra and should begin to take on a red or orange hue. The moon will start to leave the earth’s shadow at 11:43 p.m. Sunday and will return to its normal, bright complexion by 12:50 a.m. Monday, Nichols said.
“The sunlight is shining through atmosphere on the edge of the earth,” Nichols said. “As it passes through the atmosphere, just like when you see a sunset, the more blue light is scattered out and all you’re left with is red.
“When that happens with the lunar eclipse, you could say that the lunar eclipse is the collective of sunrises and sunsets happening all around the world at that particular moment in time.”
The color will also depend on how clear the atmosphere is across the globe, Nichols said. Cloudiness, dust storms and volcanic eruptions can all affect the coloring. Lunar eclipses can appear coppery orange, brick red or even a particular tone of gray.
During the lunar eclipse on Sept. 27, 2015, the eclipse appeared dimmer than expected, possibly from ash spewed by a volcano in Chile, Nichols said.
As a part of a citizen science program, some observers around the Chicago area will be polled on the pigment of Sunday night’s eclipse to establish a baseline.
This year’s total lunar eclipse has garnered even more attention for its unofficial designation as a “Super Blood Wolf Moon.” However, these titles are just window dressing for the most part.
A Wolf Moon is a the Native American name given to the first full moon of the year each January. Total lunar eclipses have been termed “Blood Moons” because of the reddish tinge the moon takes once it’s within the Earth’s shadow and because of apocalyptic theories associated with the events.
Perhaps the most noteworthy heading is “Super Moon,” a full or new moon that’s within 90 percent of its closest approach to the Earth. Super moons can appear as much as 14 percent larger in diameter and up to 30 percent brighter.
Adler will be hosting a watch event called “Lunapalooza” in and outside its lakefront campus building between 8 p.m. and midnight.
The planetarium’s astronomy team will have telescopes set up for free outside along with portable heaters and a limited supply of hot cocoa. For the cost of $12 for adults and $8 for children, attendees can watch a live feed of the eclipse indoors and also view a screening of a new presentation called “Imagine the Moon.”
Viewing opportunities are still uncertain in the Chicago area given a chance of snow showers and cloud cover. According to the National Weather Service, sky cover will be between 50 to 55 percent during the eclipse.
For the Chicago area, this will be the last visible total eclipse until May 15, 2022.
“These events are always a lot of fun because no matter what happens outside, we’re going to party with the moon inside,” Nichols said.
“It’s a great way for people to connect with the sky, with an object that people are familiar with and that you don’t need special equipment to go outside and see. We get to see that connection between the earth, sun and the moon in the sky in that moment, which is really neat. You get to start to feel like you’re a part of a larger solar system.”
tbriscoe@chicagotribune.com
Twitter @_tonybriscoe
