An Iridium Flare over Keppel Henge, May 14, 2009. In 1999 my friend Bill Loney and I built a large, megalithic circle called Keppel Henge in a field near the shores of Georgian Bay. The Sun's shadow cast from the tall granite stone in the centre of the circle falls on the megaliths at different times of the year to mark the passing seasons. Many thousands of people from around the world have visited Keppel Henge to enjoy the experience of a modern day stone circle. In this photo, a brilliant Iridium flare blazes in the sky high above the henge.
Iridium flares are caused by particular communication satellites that have large, mirror-like antennas that sometimes reflect sunlight directly onto the Earth below. If the angles are just right, the reflected sunlight can be very bright in this case, it was magnitude -8 many times brighter than the brightest stars. The positions of Iridium satellites are precisely known, so it's possible to predict when and where a flare will be seen.
The flare is in between the constellations Draco and Hercules, and the bright star between the flare and the henge is zero magnitude Vega.
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