On Aug 12, 6:26 am, Alexander Avtanski wrote:
Hello,

Does somebody know if Zi Yuan 2 or Cosmos 1689 Rocket is tumbling?
Period about 6 sec (+/- 2 sec), very pronounced sequence of one bright
peak and one less bright peak. Something like this?

I have reviewed many observations of Cosmos 1689 r (85090B / 16111),
as far back as 1990, almost all of which report steady brightness.
There was one report, in spring of 2007, of a 60 s variation, much
slower than your observation.

I found only a few observations of Zi Yuan 2 (03049A / 28057), made in
2004-05, which reported steady brightness.

Since 03049A has seldom been observed, and not recently, it is more
likely to be an undiscovered flasher than 85090B. It is a fairly young
spacecraft, but it could have failed prematurely. I have not attempted
to find out its health, so that is only speculation.

Please let us know the results of any further observations you may
make of 03049A.

Ted Molczan