In the early hours of the morning of Thursday 21 February (the night of Wednesday 20 February) there will be a total lunar eclipse. The event will be visible from Western Europe (including the UK), Western Africa, all of South America, and central and Eastern parts of both the USA and Canada.
The times for the event are as follows:

• 00:30 GMT: The Moon begins to enter the Earth’s penumbral shadow at 00:30 GMT – you may not even notice this, since the Moon will only be slightly darker
• 01:43 GMT: The Moon begins to enter the Earth’s umbral shadow – this is when the full Moon begins to get really dark!
• 03:01-03:51 GMT: The entire Moon is now in the dark umbral shadow of the Earth, although some red sunlight will get through the Earth’s atmosphere and illuminate the Moon, giving it a deep red colour
• 03:51 GMT: The Moon begins to leave the umbra and enters the other side of the penumbra
• 05:09 GMT: The Moon has left the umbra behind, and is almost fully illuminated by the Sun again
• 06:20 GMT: Moon leaves penumbral shadow

But what are the penumbra and umbra shadows? Well, take a look at my tea mug to the left. As you can see, when I cast a shadow of the mug onto the desk using a lamp, there are two shadows – a lighter penumbra shadow, and a much darker umbra shadow. These two shadows are caused by the width of the light bulb (or Sun). If the light source was a tiny pin-point of light, there would only be one deep shadow.
As a taster, below is a time-lapse movie of a total lunar eclipse that occurred in 2006.

Click on the image for a time-lapse movie (format: Windows Media Player)

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