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glatt · 11-22-2005, 07:58 AM

I've looked for and seen a few iridium flashes. It's very easy. It's been a while since I've done it, but if you go to http://www.heavens-above.com/ they can tell you when satellites will pass over your co-ordinates.

Anyway, the flashes look a lot like airplanes coming in for a final approach with their "headlights" on. Of course they look slightly different because they travel in a straight line. They start out dim, and get brighter as they move across the sky, then they get dim again. It takes about 60 seconds or so for them to travel across the sky if they are directly overhead. They are only visible around dusk and dawn, because of their low orbit.

I think this picture captured two different irridium flashes at the satellites took turns going by, several minutes apart. Iridium satellites don't travel right next to each other, as far as I know. But they do travel in predictable orbits, and I can imagine one being a few minutes behind another in a similar orbit. This is either a double exposure, or a time lapse exposure, or a combination of the two.

11-22-2005, 07:58 AM	#7
glatt ™ Join Date: Jul 2003 Location: Arlington, VA Posts: 27,717	I've looked for and seen a few iridium flashes. It's very easy. It's been a while since I've done it, but if you go to http://www.heavens-above.com/ they can tell you when satellites will pass over your co-ordinates. Anyway, the flashes look a lot like airplanes coming in for a final approach with their "headlights" on. Of course they look slightly different because they travel in a straight line. They start out dim, and get brighter as they move across the sky, then they get dim again. It takes about 60 seconds or so for them to travel across the sky if they are directly overhead. They are only visible around dusk and dawn, because of their low orbit. I think this picture captured two different irridium flashes at the satellites took turns going by, several minutes apart. Iridium satellites don't travel right next to each other, as far as I know. But they do travel in predictable orbits, and I can imagine one being a few minutes behind another in a similar orbit. This is either a double exposure, or a time lapse exposure, or a combination of the two.