IEM Daily Feature
Thursday, 06 September 2007

The moving water tower or...

Posted: 06 Sep 2007 02:55 AM


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Sunrise shots from Madrid webcam
The featured image is of the sunrise for 3 dates this year from the Madrid webcamera. Any ideas why the sun's position relative to the water tower (indicated by red arrow) changes? Is the sun moving relative to the Earth? Is the water tower moving? Of course, the answer is related to the changing of the seasons as the tilt of the Northern Hemisphere is slowly starting to point away from the Sun and thus the sun is more southerly in our sky. The effect can be illustrated by comparing webcam shots of the sunrise against a stationary object (water tower). The camera is looking east, so the sun is appearing further to the right in the image (to the south) as the days go by since late June. You can also notice the change in sunrise time as our days get shorter.

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Tags:   webcam   sun