I live at 49.99N, 8.57E. Today we had exceptionally clear skies. I was looking out a window towards the South between 7:48pm and 7:52pm local time (central european) when I noticed a strange light pattern in the sky.
I am an amateur astronomer so I know how a plane looks like (also, we live right next to a large airport), how an artificial satellite looks when catching some sunlight or even a meteor.
None of these applied to what I saw. What I saw crossed from the Northwest towards the Southeast. It appeared above me at around 7:48pm and took around 3-4 minutes to make it towards a little above the horizon in the Southeast.
What I saw reflected the sunlight every around 1-2 seconds (it was varying), with each reflection being differently bright. There would be very dim reflections maybe as bright as an artificial satellite (but not constant like them), and the brightest ones would be as bright as the brighter stars in the sky. No flares or something. Some reflections were reddish but most were regularly white.
What kept me wondering was that some of the reflections did not appear where you would think they would appear judging by the speed of the object. Those few reflections appeared slightly behind where they should actually have been. The following reflection would then be regular again. Was it several objects? Was it maybe rotating?
At around 7:51pm the ISS appeared in the (far) east on a different trajectory.
What did I see? What could explain these reflections? Does it have to do with the ISS?
(for completeness' sake, I did check flightradar24.com, but there was no flight in that direction and time)