The colors in the Earth’s shadow

The latest total lunar eclipse, on Jan. 31st, 2018, was really colorful. The full Moon spent about 76 minutes in the Earth’s shadow, allowing me some experiments focused on revealing the colors of scattered solar light on the lunar surface. I was lucky that for the totality was (almost) clear skies over Lamai beach, the Ko Samui island (Thailand) so here come some “portraits” of the eclipse’s story in the starry sky. Using Canon 6D, MTO 1100mm/f10.5 on Vixen GP-2 mount, I captured the Moon every 4 minutes while moving in the shadow, and also the stars around in during the maximum eclipse. The resultant mosaic then shows real changes of the colors and illumination of the Moon on its path in the shadow.

Many observers around the world, including me, also reported “rainbow” colors of the Moon at the beginning and before the end of the totality. Indeed, the typical orange-red color with a “turquoise” tint on lunar edge close to the edge of the Earth shadow, made this eclipse very colorful. In fact, it is caused by effect of our ozone. When you think of a lunar eclipse, the color that comes to mind is red. The core of Earth’s shadow is reddened by atmospheric scattering, and when that shadow falls across the Moon, the lunar landscape turns as red as a sunset. However, light passing through the upper stratosphere penetrates the ozone layer, which absorbs red light and actually makes the passing light ray bluer. This can be seen as a turquoise-blue fringe around the red (see more on Spaceweather.com). And I can only confirm that the phenomenon was easily visible to the naked eyes. What a wonderful experience!

And for the closure, I also have a nice personal story to this particular eclipse. When I was young, just kid interested in astronomy, I was told by my teacher of astronomical course, in the Pardubice observatory, that a total lunar eclipse supposed to be visible in the night. It was night 20-21 January 2000, sky was crystally clear and, with my friend, we decided to watch the phenomenon from roof of public garages behind his home. With his brand new telescope, the Chrismas present, my friend allowed me to watch spectacular moonrise and we both were excited of what should happen next. But as I wrote, I was a kid and didn’t ask for the most important question – when exactly the eclipse started. Well, you probably see what happened next. Later that night, my mother found me on the roof of the garage and sent me home to go sleep as the next day I had to go to school. And I didn’t see that eclipse at all. And the very next day my friend told me the eclipse really occured, just very soon in the morning over Pardubice, before daybreak. How sad I was… Until now. I have just realized this eclipse I observed over the Thailand, was the next one of SAROS period since year 2000. Well, I finally saw it…

And in case you are interested, the next one of this period SAROS will occur on February 2036, perfectly visible over Europe…