The moon does a disappearing act early this evening when it dips behind the earth's shadow in a total lunar eclipse. The dramatic show is conveniently early, with the moon covered by the darkest part of the shadow by 7.50 p.m. While clouds may obscure the view, particularly in the south, weather forecasters say most people should be able to see the eclipse.
The moon will take on a dramatic hue as it glides slowly into the deepest part of the earth's shadow or umbra, turning a ruddy-orange. There will be plenty of time to have a look as it will not begin passing out of the umbra until 8.52 p.m.
"Most people will have some glimpse of the eclipse," according to a Met Eireann forecaster. However, a frontal system is approaching from the Atlantic. "There will be a fair amount of cloud over the southern part of the country and it will be more broken to the north." Showers under cloud are also expected, he said.
If the weather co-operates it could be one of the best lunar eclipses in a decade. The atmosphere has had almost 10 years to clear since the last big volcanic eruption at Pinatubo in the Philippines.
The view should be sharp and free of the dust that left the eclipsed moon near invisible for several years.
The moon never quite disappears during a total eclipse, taking on instead a brick-red colour provided by the earth's atmosphere. Sunlight coming past the edge of the planet is bent inwards by the atmosphere. It scatters out the blue light and lets through the reds and oranges of a whole planet's shared sunrises and sunsets as seen at the earth's rim.
The dimmed moon will also make the stars appear to shine more brightly although light conditions are no better than at a new moon. Almost nothing tops the spectacle of a total lunar eclipse however.
The times to remember this evening are 6.42 p.m. when the moon begins to enter the umbra, 7.50 p.m. to 8.52 p.m. when it is fully in the deepest part of the shadow and 9.59 p.m. when the moon finally clears the umbra.
