Iridium satellites produce bright flares when their solar panels catch the sunlight. All you need to see a flare is a trusty mark 1 eyeball (preferably two). Times of flares for anywhere in the world can be obtained from Heavens Above. The reason the times and locations of flares can be predicted so accurately is that the orbits and orientations of the satellites are precisely maintained. When a flare occurs it can be as bright as magnitude -8 which makes it much brighter than Venus

Flare of Iridium 22 at 18:04:53GMT on 8/02/01 Jupiter is to the top left and Saturn can be faintly seen to Jupiter's lower right. During the flare Iridium 22 moves about 6°. This flare was magnitude -7 with Jupiter at magnitude -2.4

This graph shows the total values of the pixels in the image of Jupiter and Iridium 22 during the flare. To do this I simply summed all the pixels in a box round the image of each one. I then normalized the figures so that Iridium 22 was 100 at peak brightness. On the graph the peak brightness ratio is 3.83. Now for any brightness ratio the magnitude difference is (m2-m1)=2.5log(B2/B1) which  gives a magnitude difference of 1.45 in this case which is much less than the actual 5.4. The reasons the result is wrong are camera saturation and possibly because it may be non-linear in its response.  

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