[ATMoB-discuss] Tonight's Eclipse

[George Roberts]

>The coppery moon did set me thinking about why does it appear so. 
>Does any one know why does the moon appear in this specific color. 

The same reason sunsets on earth are reddish/orange.  If you were on the moon
during the eclipse looking back at the earth you would have seen a red sunset
ring all around the earth.  This sunset ring is pretty much the only thing that lights
the moon during totality.

Air tends to let red light through more so than blue and scatters the blue around
(hence the sky tends to be blue).  The more miles of air that the sunlight has to
travel through, the redder it looks.  That ring will have gaps in it where there are
clouds.  If there are enough clouds in the right spots, then the moon will be very
dark indeed.  Other things in the atmosphere like pollution or volcanic dust
will also affect color and brightness of a lunar eclipse.

- George Roberts
http://gr5.org