View the Selenelion!

The next lunar eclipse will be a special one:

For most places in the United States and Canada, there will be a chance to observe an unusual effect, one that celestial geometry seems to dictate can’t happen. The little-used name for this effect is a “selenelion” (or “selenehelion”) and occurs when both the sun and the eclipsed moon can be seen at the same time…

But wait!  How is this possible?  When we have a lunar eclipse, the sun, Earth and moon are in a geometrically straight line in space, with the Earth in the middle….

Atmospheric refraction causes astronomical objects to appear higher in the sky than they are in reality….when you see the sun sitting on the horizon, it is not there really. It’s actually below the edge of the horizon, but our atmosphere acts like a lens and bends the sun’s image just above the horizon, allowing us to see it.

 

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