The first total lunar eclipse in more than two years turned the moon into a cosmic red ball early Tuesday —and there's still more to come.
Total lunar eclipses occur when Earth is positioned precisely between the sun and the full moon. Because of the tilt of the moon's orbit, total eclipses don't happen all that often — about twice in the course of three years, on average. When they do, it can be a spectacular sight: The darkened moon takes on a reddish glow because of the sunlight refracted by Earth's atmosphere.
The last total lunar eclipse took place in December 2011, but Tuesday's eclipse kicked off a string of four such events, known as a tetrad. The series is dictated by a recurrence of the right orbital parameters every six months or so. The other three eclipses in the set are due on Oct. 8, and then next year on April 4 and Sept. 28.
"The most unique thing about the 2014-2015 tetrad is that all of them are visible for all or parts of the USA," eclipse expert Fred Espenak said in a NASA preview.
Moon-Day isn't Doomsday
Some doomsayers tried to sell the "Blood Moon" tetrad as an evil omen, but that's bogus. The only thing scary about this eclipse is what it might have done to your sleep schedule: The total phase of the eclipse was visible between 3:06 and 4:24 a.m. ET. Espenak lays out the details on NASA's eclipse-centric website.
Unlike solar eclipses, lunar eclipses are visible to half the world at the same time. This time around, North America was prime territory, but portions of the eclipse could be seen from parts of South America, Europe and Asia just before sunrise, and parts of Asia and the Pacific just after sunset.
You may have heard all those warnings about protecting your eyes during a solar eclipse — but a lunar eclipse is totally different, and totally safe. You can look all you want. Want a closer look? Use binoculars. Want to take a picture? Espenak tells you how.
Tuesday's show played out not only where the skies were clear, but also over the Web and via social media. NASA hosted an "Up All Night" chat, offered a live Ustream view of the lunar eclipse from Marshall Space Flight Center and aired eclipse coverage on NASA TV. Skywatchers shared pictures via NASA's Flickr group.
- Nine cool facts about lunar eclipses
- Why an eclipse paints the moon red
- Flash interactive: What causes a lunar eclipse?
Get in on Mars and more
The moon isn't this week's only spacey attraction: It's also prime time for seeing Mars at its biggest and brightest. Mars reached the closest point to Earth in its orbit on Monday, passing by at a distance of 57 million miles (92 million kilometers). Check out our viewing guide for the details.
This is the closest Mars has been since late 2007, but Mars will now be receding from Earth for about a year, and then making another approach for an even closer encounter in 2016.
The International Space Station should be visible passing through evening skies over some parts of the United States — to get the viewing schedule for your location, consult NASA's "Spot the Station" website. Jupiter, Saturn and Venus are also out: For details on those night sights, head on over to EarthSky and Sky & Telescope.
The "Blood Moon" eclipse is a hard act to follow, but keep watching the skies. In the weeks ahead, two meteor showers will be hitting their peak: the Lyrids and the Eta Aquarids. Getting up in the middle of the night for Moon-Day serves as good experience for those coming attractions.
Got pictures to share? Alert us to them by using the hashtag #NBCEclipse on Twitter or Instagram, sending your favorite via our FirstPerson photo-upload page, or sharing them on the NBC News Science Facebook page.
Tip o' the Log to Sky & Telescope for the eclipse photo and graphics.