Total Lunar Eclipse on 16th June 2011
On June 16th, 2011, a total lunar eclipse, centered on the Indian Ocean, was visible from Europe, Africa, and Asia. The photo shown above was taken a short time after moonrise by Wolfgang Hinz in the Bavarian Alps, Germany.
Further pictures sent Pitan Singhasaneh, taken in Bangkok, Thailand, where the total phase happened just before the Moon set.
The eclipse was quite dark in all regions of visibility. Therefore, the Moon was only seen as a feebly lit reddish-brown disk during the never quite dark late summer evening hours in central Europe. The remaining illumination on the Moon is due to light refracted into the Earth’s umbra in different layers of its atmosphere, and therefore bears the imprint of the red-orange color of the skies at the Earth’s dawn or dusk terminators. Because the Moon travelled almost right through the umbra’s center, this eclipse had a very long duration of totality (101 minutes) and consequently became quite dark in the innermost parts of the umbra which only get light from the lowermost and thickest layers of the Earth’s atmosphere. Additionally, the atmosphere was contaminated by dust from three volcanic events in Chile, Iceland, and Ethiopia which might have further diminished the illumination of the eclipsed Moon.
Elmar Schmidt did photometry on the Moon at Farm Hakos in Namibia at 1834 m altitude. The darkness of the eclipse was quite pronounced even under the excellent skies of Namibia, where the Moon climbed to an elevation of more than 50 degrees during mid-totality. Then, a pair of 10×40 binoculars did not show the contours of the lunar maria at the brownish grey center of the Moon’s disk. On the other hand, the eclipsed Moon always retained a generally deep orange color. Its minimum brightness of -0.35 visual astronomical magnitudes complies with an extrapolation from less deeper eclipses, thus not really pointing to a significant influence of volcanic dust. An exception could be taken with respect to the asymmetry of the eclipse which was much darker at the exit as compared to the ingress – although more colorful because of showing the blueish-green tinge at the umbra’s rim. This might hint to darker or altered atmospheric conditions near the Earth’s eastern terminator over the Indian Ocean and Western Australia.
Authors: Claudia Hinz, Elmar Schmidt