Tomorrow morning there will be a total lunar eclipse visible from North America and Asia. It’s worth dragging yourself out of bed if your local forecast cooperates. It’s the second lunar eclipse of 2014 and the second of current lunar tetrad (four eclipse in series, roughly six months apart). What’s more, this lunar eclipse is unique as the rising Sun and setting Moon (mid-eclipse) will be visible in the sky simultaneously.
A lunar eclipse occurs when the Earth passes directly between the Sun and the Moon, casting a shadow over the Moon. This geometry requires that the Sun and Moon be on opposites sides of the sky from one another, 180 degrees apart. In this configuration, they can’t both be visible in the sky at the same time. And yet, tomorrow morning, they will be. When the Sun rises, the eclipsed Moon will be setting, but they will be visible together for just under ten minutes (depending on your location). This is because Earth’s atmosphere bends the light from the Sun and the light reflecting off the Moon just enough to make both objects appear higher in the sky than they actually are. Astronomers call this phenomenon a selenelion (or selenehelion), also known as a horizontal eclipse.
Total lunar eclipses have started to be referred to as “blood moons” (not an astronomical term) due to the deep red color the Moon turns during totality. Here’s a video I did that explains what is actually going on.
Here’s what tomorrow’s eclipse will look like in its entirely:
Note, nothing really interesting happens until the Moon enters the Earth’s umbra (the darkest part of Earth’s shadow), so you should not feel pressure to get up when the eclipse technically starts. Get that extra hour of sleep before the real show starts.
If your forecast is poor, like us New Yorkers, you can catch the entire eclipse via NASA’s live stream which will start at 3:00am EDT. You can also find all you wanted to know about lunar eclipses and more at NASA’s dedicated Eclipse Website.