Thursday, 9 February 2017

Penumbral lunar eclipse

If any of you are night owls and happen to have a clear sky around midnight on Friday, then you could enjoy (if that's the right word!) a near-total penumbral eclipse of the Moon.

Eclipses of the Moon occur when the Earth blocks some or all of the sunlight reaching the Moon. (The Moon, of course, is not self-luminous - it shines by reflecting the Sun's rays) As the diagrams below demonstrate, the Earth's shadow creates a dark, fully-shadowed region called the umbra and a region where some light enters: this is called the penumbra.

Friday's lunar eclipse is penumbral, which means the Moon will appear somewhat dimmer than normal, but not as much as during a full umbral eclipse. Still : interesting to see if the sky is clear!

Umbral eclipse

Penumbral eclipse

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