Iridium 5 companion?

Sean Sullivan (tssulliv@unix.amherst.edu)
Mon, 13 Oct 1997 15:41:31 -0400 (EDT)

I downloaded IRIDFLAR yesterday from the vsohp home page, and went out
this morning (10/13/97) to try my first Iridium flare observation.  I 
have not before seen an Iridium, so I was just trying to get a general 
sense of what their behavior is like.  

IRIDFLAR predicted a zero-magnitude flare of Iridium 5 at 4:57:45 EDT.
Using my usual program, I made pre-flare predictions and spotted the 
satellite at zenith and followed for about 90 sec before it became
too faint.  Later, the flare was on schedule, low in the north.  

As it started falling in magnitude, I went back to binoculars.  When they
reached my eye, and I tried to find the slow-moving satellite in the
starfield, I picked up two moving objects.  Having seen many STS 
rendezvous / formation flying combinations, I at first just gave it a
casual "oh".  I had read reports of seeing a string of Iridiums glinting,
and at first thought that I was just seeing a second member of the 
contellation.  This was my first Iridium, so I was thinking "what are
they like?" and open to anything.

Then I realized that this wasn't right after launch when they are close, and
neither of my programs had alerted me to a second Iridium at that time.
This pulled me out of my sleepy state with a "what the hell is that?"
response.  The lead object (brighter) was just approaching the top of a 
nearby building, so I mentally timed the distance to the trailing object.
The trailer hit the same point on the building six seconds later. 
 
I believe that this was not an abberation in my optics because I saw the
secondary after the bright/lead object was invisible.  I also believe 
that I saw something other than a star because I timed *something* --
it all happened so fast that this is the most convincing part of my
memory.  

I was not making good measurements, and had no reference stars, but I think
the trailing object was maybe 3 mag fainter than the primary.  The track
appeared identical, but I would not preclude a slight divergence.  
Perhaps mags 1 and 4?

Afterwards, I went through the Molczan file and found no good matches.  The
best match was 22220 Cosmos 2219 RB, but it was about 10 deg away (wider
than my field of view) and more than a minute apart.  

So, my *sense* was that the secondary was co-orbital to Iridium 5, based
on the remarkably similar track, but I would not be terribly surprised if 
it was some other piece of random junk.  

I think that is enough rambling on this obs.  My location is 42.3376 N,
71.1482 W, near sea level.  


-- Sean Sullivan