In the predawn hours of Oct. 8, early risers and restless souls weary from insomnia are in for a rare spectacle as the Hunter's Moon glows a coppery red, and is veiled by Earth's great shadow.
Wednesday's total lunar eclipse, set to begin a little after 5 a.m. EDT, will be the second of four consecutive "blood moons" to be visible in the United States during a two-year time span.
"It's not that often that we get a total eclipse from the United States; sometimes we go years between getting them," Slooh Astronomer Bob Berman said, adding that it is a very unusual situation. Slooh airs astronomy events live from around the world using community telescopes to allow people to view events even if they are not visible in their region.
The fourth consecutive total lunar eclipse will occur on Sept. 28, 2015.
During Wednesday's celestial event, the moon will line up with the Earth and the sun, becoming progressively redder between 5:15 a.m. EDT when it enters Earth's shadow and 6:25 a.m. EDT when it becomes totally eclipsed.
"One of the cool things about the moon is that it's the only celestial body in the known universe that's speed in space makes it move one moon-width per hour; it travels its own width per hour," Berman said, referring to the time the moon will take to move into Earth's shadow.
Stargazers on the West Coast and East Coast will see the eclipse unfold at the exact same time, but the moon will be lower in the sky in the East as the moon begins to set while it is eclipsed. For those in the East, a clear westward vantage point will be needed to catch the final moments before moonset and sunrise.
Clouds and rain may limit viewing of the eclipse in the northeastern U.S. as a storm system swings in from the southwest. Much of the southern and central U.S. will have clear viewing under clear or partly cloudy skies. Meanwhile, thick clouds and rain may hinder the view of the eclipse over the Southwest as Simon's moisture arrives.
The reason the event is often called a blood moon is because of the red color that is cast upon it by light refracting in Earth's atmosphere.
"When the sun is completely behind the Earth, what you see [if you were on the moon] is the black Earth lit up from behind, and surrounding this black Earth in space, is a ring, a fiery ring, which is really all of the world's sunrises and sunsets combined into one wedding ring of red," Berman said. "And so that red light of all the world's sunrises and sunsets, that light, gets bent or refracted into the shadow and gives the shadow its red color."
The color of the moon, which is normally a coppery red during a total eclipse, can also vary, which Berman said is a great environmental report card for Earth.
If there is a lot of dust in Earth's atmosphere because of a volcanic eruption, the moon will disappear behind an inky, black shadow. In rare occurrences, if the edges of Earth are nearly free of clouds, the moon will only be dimmed and appear yellowish.
"This is the only kind of object in the night sky that you look at it, and you learn about yourself; you learn about Earth," Berman said. "If we're very polluted then the moon's eclipse will be very black."
While early risers and light sleepers in the U.S. will likely be the ones to catch a glimpse of the eclipse as it occurs, Berman said he encourages anyone interested to take a look right before dawn if skies are clear in their area. If you can't see the eclipse, you can watch it live below.
"I think it looks weirdest and best around 6:15 a.m. EDT," Berman said.
With only 10 minutes before the moon is in total eclipse, a portion of sunlight hitting the moon from one side makes the moon look similar to Mars or a large red planet, he added.
"If you had to pick one time to set the alarm and go out, I'd say do it at 6:15 a.m. EDT," he said.