Previewing the Blue Blood Supermoon Eclipse of January 2018 using mobile apps

In 2018, the world will experience three partial solar eclipses and two total lunar eclipses — but whether you can see them depends on where you live. The first event is a total lunar eclipse that happens on the morning of Jan. 31. This eclipse will be special! The moon will be both "super" and "blue," and if skies are clear, skywatchers in North America will be able to see all or part of the eclipse.

In this edition of Mobile Astronomy, we'll highlight the rare "Blue Blood Supermoon" total lunar eclipse and tell you how to use your favorite astronomy app to preview it. We'll also help you use your app to explore how lunar eclipses work.

Mobile astronomy apps such as SkySafari 6 are an ideal tool to preview celestial events. The total lunar eclipse on the morning of Jan. 31, 2018 features an enlarged supermoon. It's also a Blue Moon, the second full moon in January — a combination that hasn't occurred in many years. In the eastern US and Canada, the moon will set mid-eclipse. But skywatchers in the west will be able to watch the entire eclipse, as shown here near the end of the eclipse at 6:15 a.m. PST in San Francisco, CA. By telling you where in the sky it will occur, your astronomy app can help you plan to observe or photograph any eclipse. Credit: SkySafari App and NASA

A Blue Blood Supermoon eclipse

On Jan. 31, 2018, skywatchers across much of the world will receive a postholiday gift: the total lunar eclipse of a full supermoon that is also a Blue Moon! Unlike last summer's Great American Total Solar Eclipse, lunar eclipses are completely safe to look at because the sun is below the horizon. Any sunlight that reaches the eclipsed moon has to pass over the Earth's horizon, painting the moon with reddish light — hence the nickname "blood moon" for eclipsed moons.