Blog Archives

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

Advertisements

Pollen corona during total eclipse

A pollen corona was seen by several observers at the Southern coast of Turkey during the total solar eclipse of 29th March 2006. This nice picture taken by Emma Herranen shows the atmospheric pollen corona with three colour segments only a few seconds before the second contact, as illuminated by the diamond ring phenomenon. The inner parts of the solar corona are seen as a white circle around the Moon.

Shadows during the annular eclipse

Günther Können took these pictures in Madrid during the annular eclipse of 3rd Oct 2005. They are solar images projected onto three mutually perpendicular surfaces: one horizontal and two vertical. During the annular phase (right hand image) the solar images were ellipses, with their long axes oriented in different directions on the two walls and the steps and ground. This was not unexpected. However, in the picture showing the pre-annular phase, one notices that the sun crescents on the ground and steps comprised the more pointed part of the ellipse, whereas on the walls they are the more rounded part of the ellipse. The key is in the third picture, where the shadow of the roof overhang kinks from one projecting plane to the other. In hindsight, all of this is understandable, but I have never seen a comment on this ‘solar image puzzle’.

Twilight Colours during the total Sun Eclipse

A total Sun eclipse occured on 29th March 2006. The weather was very good in all southern Turkey. The sequence photo was taken by Jukka Ruoskanen on a beach close to the town called Side in Turkey. Few minutes before totality high clouds came, and a halo was seen. The halo, of course, vanished with the sunlight and reappeared again after the total phase – the high clouds responsible for the halo can be seen in some of the photos. The sky colours were truly amazing with deep bluish hue towards the zenith and a great “sunset-like” appearence all over the horizon. The other noteworthy points were a significant temperature drop and the peculiar light some minutes before second contact. At that time the shadows were really sharp too.

The second (16 mm) wide-angle picture of the sky during the totality of the 2006 eclipse is taken by Günther Können in Colakli near Side at the south coast of Turkey, straight on the central line. The horizontal field of view is 135 degrees. At the 4 o’clock position fron the overexposed corona, Venus is visible. The limiting magnitude during totality is +3, about the same as during twiligt with the sun 7 degrees below horizon. The light of the sky occurs because of leaking of light via the horizon, from regions where the sun is not completely eclipsed.