Images and illustrations credit & copyright: Eclipse images are mine and illustrations are via Sky & Telescope.
Head’s up! Sunday, January 20, (tomorrow night) and into the morning of Monday, January 21, 2019, the Earth will pass directly between the Sun and Moon, creating a total lunar eclipse with a totality of 63 minutes. This total lunar eclipse will be visible throughout the America’s (North and South) as well as Iceland, Greenland, Western Europe and Western Africa.
What is a lunar eclipse?
Typically there are two lunar and two solar eclipses every year to varying degrees. Sometimes it’s a partial and sometimes it’s a total with the Sun having a couple more possibilities like the annular and hybrid eclipses in there as well. When one happens, the other will take place two weeks later. Unlike a solar eclipse where the Moon passes between the Sun and the Earth, casting the Moon’s shadow upon us, a lunar eclipse is where the Earth passes between the Sun and the Moon, casting the Earth’s shadow upon the Moon.
The shadow of the Earth has a couple different conical regions that extend from the earth outward and are set up in a target-like fashion. It has the outer shadow cone; the penumbra and the inner shadow cone; the umbra. When the Moon wanders into the Penumbra (outer region) somewhere on the Earth will witness a partial lunar eclipse. If all the Moon does is enter and exit through the penumbra, the entire event will just be a partial lunar eclipse. However if the Moon’s path takes it through the center of Earth’s shadow it will encounter the umbra and thus somewhere on Earth will witness a total lunar eclipse. A total lunar eclipse always starts and ends with a partial eclipse.
Not anywhere near as dramatic as a total solar eclipse, the total lunar eclipse has some benefits of its own. Where a total solar eclipse can only be seen along a relatively narrow path called the “Path of Totality,” a total lunar eclipse is usually witnessed by half the planet. Also a total solar eclipse’s totality lasts only a few minutes while a lunar eclipse’s totality can potentially last more than two hours.
Why does a total lunar eclipse appear red/orange?
When the Earth gets between the Sun and the Moon, all direct light from the Sun is blocked from reaching the Moon. The only light that reaches the lunar surface is sunlight that’s been refracted through Earth’s atmosphere. This process scatters blue light away (Rayleigh scattering) leaving only red wavelengths available to make their way to the Moon.
What will I need to see this event?
Not much. The only requirements are clear skies and to be in an area where the eclipse is visible from. Even if it’s cloudy, if you can catch a break during totality you can still see it because it’s a fairly long lasting event. If you have a telescope and or binoculars, great have at it but you don’t need it. You also don’t need dark skies because you’re looking at the brightest object on the night sky, the full moon. So grab a blanket, some friends and go witness a beautiful celestial event.
My 2019 eclipse page: https://danspace77.com/2019-eclipse-schedule/
Time and Date (use the bar about half way down on the right to find your specific times): https://www.timeanddate.com/eclipse/lunar/2019-january-21
Sky & Telescope page for this event: https://www.skyandtelescope.com/observing/solar-and-lunar-eclipses-in-2019/
Dominic Ford’s “In The Sky” page for this event: https://in-the-sky.org/news.php?id=20190121_09_100
Fred Espenak’s “EclipseWise” page for this event: http://eclipsewise.com/lunar/LEprime/2001-2100/LE2019Jan21Tprime.html
Apogee & Perigee Calculator: https://www.fourmilab.ch/earthview/pacalc.html
The Danjon Scale of Lunar Eclipse Color: https://perfectastronomy.com/danjon-scale/