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February 2007
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Lunar eclipse. |
I should have been on a train, coming back home after spending a week in the Scottish Highlands. However, a couple of days before I was due to leave, I had
been struck down with the flu, so instead of taking photos in the snow-covered mountains, I had spent the week curled up on the sofa with a blanket and an
endless supply of hot Ribena. On the other hand, this misfortune did mean that I would get to see and photograph a lunar eclipse.
I have viewed a few lunar eclipses over the years. They are relatively frequent, occurring every couple of years or so for any given location. The lunar
eclipse on the 3 March 2007 was the first that had been viewable in the UK since October 2004. But the weather being what it is in the UK, frequently these
cosmic events are marred by cloud. However, for once, the weather did its part and the cloud stayed away on this occasion and gave everyone a heavenly feast.
Lunar eclipses occur when the Moon passes through the shadow of the Earth. The Moon moves across the Earth's shadow, slowly disappearing, then when the Moon
is totally in the shadow of the Earth, it turns red for a while before making its way out of the Earth's shadow again, reappearing before it is a full and
bright Moon again. The reason that the Moon appears red when it is in the Earth's shadow is because no light from the sun is reaching it anymore. However,
the light that skims through the Earth's atmosphere at the edges is scattered and bends the red light, in the same way that sunsets appear red. This red
light then lights up the Moon, which usually appears a coppery-orange colour. Depending on how much dust and particles are in the Earth's atmosphere affects
how red the Moon appears (for example, if there has been a recent volcanic eruption somewhere).
Lunar eclipses are relatively easy to photograph. You don't need any special filters or equipment except a telephoto lens and a tripod. My digital camera
came into its own on this evening, being able to preview the photograph instantly so I knew whether I had the exposure correct. By slightly under-exposing
the image, the redness of the Moon is brought out more. However, unfortunately, as my digital camera is new, the only lens I currently have is a 24-70mm. Even
at 70mm, the Moon appears very small on the sensor. Ideally, you would want to use a telephoto lens of 1000mm or even more. Of course, using such a focal
length means that mirror vibration is a big issue, so if you can lock up the mirror and use a shutter release cable, then do so.
The next lunar eclipse will be visible from the UK in February 2008, but in the very early and unsociable hours of the morning. Hopefully the weather will be
as good again, but maybe I'll buy a longer telephoto lens in readiness before then.
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