Artificial satellites of the Iridium system

I would like to tell you about a phenomenon that many have seen, but perhaps could not give him a precise explanation. Look at the picture. No, it is not an unidentified flying object, it is the Iridium.

Iridium is a system of satellites designed to provide mobile telephone, paging and Internet communications anywhere in the world.
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Yarka flash, which you can watch for 20-30 seconds - is a reflection of sunlight by the antennas of one of the satellites flying above you. The flash is so bright that it can be observed even during the day.
Since the position of each spacecraft is known with high accuracy - such a flash can be calculated. There are special programs for this, but since they are all only under Windows, I offer you this online service here: http://www.heavens-above.ru/calc.asp . We find our location, click twice on the coordinate and follow the link “Calculate flashes for this point”.
Now you can watch such an amazing phenomenon even every day and surprise this beauty, for example, your girlfriend :)