Lunar Eclipse

Nikhil Anand & Mustafa Shahid

Indian Institute of Space Science and Technology

April 2, 2015

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Types of Eclipses

Nikhil Anand & Mustafa Shahid (IIST) Lunar Eclipse April 2, 2015 2 / 7

What

Moon passes directly behind the Earth, into its shadowI Moon : Earth : Sun are in Syzygy

Can only occur at the night of a full moon

Lasts for a few hours

Best part : Can be see without any eye protection or specialprecautions

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Umbra & Penumbra

Shadow of Earth is divided into two distinct parts

Umbra receives no direct solar radiation

Solar illumination is only partially blocked in the outer portion of theEarth’s shadow; Penumbra

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Types of Lunar eclipse

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Danjon scale

Devised by Andre-Louis Danjon for rating the overall darkness oflunar eclipses

L0 to L4; 0 being very dark and 4 being copper red

Different parts of the Moon may have different L values, dependingon their distance from the center of the Earth’s umbra

Factors affecting LI Atmospheric refractionI Observational biasI Moon’s path through Earth’s UmbraI Volcanic eruptionsI Solar cycle

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