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'm asking because today we saw an unusually bright tumbling satellite
and heavens-above.com shows two very similar passes by Zi Yuan 2 and
the Cosmos rocket. Both fit the trajectory and are within the accuracy
limits of the time we took (we did not have exact time at the moment;
probably +/- 3 minutes). I'd like to see that one again.
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.