Darkest and longest lunar eclipse

12 June 2011 04:35 pm Views - 8991

By Yohan Perera

The darkest and one of the longest  lunar eclipse in the century will be visible in Sri Lankan skies on Wednesday June 15, Senior Lecturer in Physics, University of Colombo and Consultant -Astronomy and Space Applications, Arthur C Clarke Institute for Modern Technologies Dr. Chandana Jayaratne told Daily Mirror.

Dr. Jayaratne said the Sri Lankans will get the opportunity of viewing a total lunar eclipse on that day.

The eclipse begins at 10.55 p.m. on 15th night with the moon entering into the penumbra of the earth's shadow and will end up at 4.31 a.m. The visible part of the eclipse for the observers begins around 11.53 p.m. on 15th night with the moon entering into the Umbra - the dark part of the earth’s shadow and it will appear till the moon leaves the Umbra at 3.32 a.m.

Meanwhile the Sri Lanka Astronomical Association said the eclipse is expected last around 100 minutes. The proper eclipse is expected to begin at around 11.52 pm on June 15 and would end at 3.32 pm.

It will be visible over Europe and South America shortly after sunset and over Africa and the over Asia and Australia before Sunrise.

The next lunar eclipse, the last eclipse of this year, will also be visible to Sri Lanka on December 10, 2011. But the duration of the totality of that eclipse will last for only 25 minutes. The next time that Sri Lankans will get an opportunity to observe a lengthy total lunar eclipse in its entire period will be six and half years later, i.e. on January 31, 2018.

Darkness of the total lunar eclipses of this type are used as a measure of earth’s atmospheric pollution. The light rays from the sun get refracted by dust particles in the earth’s atmosphere to produce a somewhat reddish tint to the earth shadow giving a brownish-red colour to the eclipsed moon instead of full darkness. The level of darkness of the eclipsed moon is used as an indicator of the level of atmospheric pollution.