Imaging the Lunar Eclipse

Posted on Tue, December 21, 2010

I was pleasantly surprised when the clouds rolled out and the weather turned out to be favorable for the total lunar eclipse last night!  After work, I went home for a quick nap and put on layers and layers of clothing to help me brave the cold on the eve of the winter solstice.  Friends and coworkers told me I was crazy to come back to work at midnight for the eclipse, especially with the temperatures predicted to be in the 20s.  But the clear skies, which have been hard to come by so far this month, were more than this astronomy educator could resist. So I met fellow astronomy educator Erin Braswell at National Air and Space Museum’s Public Observatory at 1 a.m. to begin preparations for a night of observing and imaging the lunar eclipse.  Our goal was twofold: to experience the eclipse for ourselves, and to capture it to share with our colleagues and visitors. The 16-inch Boller and Chivens which is the main telescope at the Public Observatory, is a very high-powered telescope, great for seeing the tiny details of the Moon’s craters and other features. However, it magnifies too much to see the entire Moon in one shot so isn’t a great choice for eclipse viewing or imaging. Instead, we used the Public Observatory’s TeleVue-85 refracting telescope along with a Lumenera 2-0 color camera and a Lumenera 2-2 monochromatic camera.

Lunar Eclipse December 2010

<p>Lunar eclipse seen from The National Air and Space Museum's Public Observatory on the morning of December 21, 2010. </p><p>Images by Erin Braswell and Katie Moore. </p>

The photograph, above, will give you a quick snapshot of our experience.  If you observed the eclipse, you might notice that the photo does not do it justice. The human eye is much more capable of seeing a range of details and colors on the bright and the eclipsed portions of the Moon, while the camera can only detect one part at a time.  In reality, the “dark” portion of the Moon is still easily visible to the naked eye, although noticeably fainter than normal.  Our cameras only capture, the brighter, uneclipsed portions of the Moon during the partial phases. During totality, they capture the fainter, eclipsed Moon.  In addition, the color is more vivid to the naked eye, during totality. As predicted, during totality, the Moon was not uniform in brightness - it was slightly dimmer at the bottom, which was closer to the center of the Earth’s shadow.  Also, since the Moon didn’t pass through the middle of the Earth’s umbra, the eclipse doesn’t progress straight across the Moon. The things I most enjoy about lunar eclipses are seeing such a familiar object as the Moon take on an unusual appearance,  and thinking about how our closest celestial neighbors are arranged to make it happen.  The Sun’s rays usually illuminate the Moon directly, but during a lunar eclipse, the Earth gets in the way.  This causes the partial stages of the eclipse.  Here you can rediscover that the Earth is a spherical object when watching the curved shadow of the Earth moving across the Moon! Then, during totality, the Moon is illuminated by sunlight that seeps through the Earth’s atmosphere, giving it the fainter, reddish glow.  You can almost feel the heavens line up! Did you photograph the total lunar eclipse? We’d love to see the results! Upload your images to the Public Observatory Project’s group page on Flickr.

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