Lunar Eclipse 03/03/07
On March 3rd 2007 a Lunar Eclipse occured (our images can be found below)
A lunar eclipse occurs when the Earth passes between the Sun and the Moon.
This means that the Earth's shadwo will pass over the Moon. This event will
be seen by anyone for whom the Moon is above the horizon. Lunar eclipses
occur at the time of a full Moon, but not every one, since the Moon has to
be near one of the nodes of intersection between its orbit and the ecliptic
The shadow of the Earth can be divided into two distinctive parts: the umbra and penumbra. Within the umbra, there is no direct solar radiation. However, as a result of the Sun's large angular size, solar illumination is only partially blocked in the outer portion of the Earth's shadow, which is given the name penumbra.
A penumbral eclipse occurs when the Moon passes through the Earth's penumbra. There does not appear to be any noticeable darkening of the lunar surface.
A partial lunar eclipse occurs when only a portion of the Moon enters the umbra. When the Moon travels completely into the Earth's umbra, one observes a total lunar eclipse. The duration of a lunar eclipse is much longer than a solar eclipse, and can take as much as six hours.
In a lunar eclipse the Sun's rays are refracted in the Earth's atmosphere. This refraction allows some light to penetrate into the cone of the geometric umbra. Thus, meaning that during a total lunar eclipse, the lunar disk is not completely dark. This light is more absorbed by the Earth's atmosphere in the blue and yellow portions of the spectrum which finally gives a particularly reddish light during the total lunar eclipse.
So when, where, how?
Lets start with how?... just look at the Moon at the given times (below) and you will be able to see the colour change.
Where, well you can't see this world over but you can in the UK, so anywhere that can avoid clouds and tall buildings. To see a precise map of where you can see this see [here]
When? The first contact will occur (with the penumbra) at 20:16:29 UT, the first contact with the Umbra is at 21:30:04 and the total eclipse will be at 23:20:55.8 UT (UT = GMT).
So what Science can you do? First and foremost Lunar eclipse's are about doing some real astronomy. The chance to observe something without any equipment - just using your eyes. It is quite rewarding to actually get out and see the Earth casting its huge shadow over the Moon, quite breathtaking. Though there is science to be done, not that we will actually do any. In 17th century, in order to improve longitude determination, the lunar eclipse was used. Today, more sophisticated experiements occur including laser ranging measurements which has allowed scientists to precise measurement of lunar acceleration and the slow down in the Earth's rotation.
Astrosoc members were able to take some shots... here are some by Samuel George and Scott Porter.
Useful external links:
[NASA Diagram of Eclipse]
[NASA Eclipse Page]
[Lunar Eclipse Computer]