Superbird A, obs 23 & 25 Fe

ROB MATSON (ROBERT.D.MATSON@cpmx.saic.com)
25 Feb 1997 12:06:34 -0800

Hi Ron,

Thanx for your latest obs -- I observed Superbird on 2/23 UT and last night
(2/25 UT).  For last night, the point at which the odd/even flashes were of
equal brightness was around 2:35 UT (as compared to your mid-point of equal
flashes at 2:42:07.8).  I was observing in 8 x 56 binoculars from very
light-polluted skies, but had no problems (other than tired arms!).  I took a
look at my program output, and it appears that I've got "our" solar panel
figured out.  The ground trace over my location occurs exactly 7 minutes
before yours.  I also notice the same phase shift in bright flashes following
the midpoint of equal-brightness flashes.

With each new data point, I'm able to further refine the spin-axis and
precession rate.  I'll need more data from the ~3:40UT timeframe to figure out
what's happening with that ?panel?  I've only got data for 2/16, 2/17 and
2/18.  Not sufficient to determine a trend.

I still believe that all the flashes you and I are seeing are from one panel
-- both sides.  I don't have enough information to know just
what is being observed at the 3:40 window.  From the few reports I've seen, it
doesn't seem like those flashes are as bright.  And since they've observed
quarter-period flashes, I tend to think that their "bright" flashes at
23.4-second intervals are caused by the satellite body itself, and not a solar
panel.  Perhaps one side of the satellite is particularly reflective.  Again,
it all comes back to needing a "picture" of the satellite.  One thing I have
learned is that the long dimension of the solar panels is in the same
direction as the booms coming off the satellite body.  In other words, the
panels are kind of arranged in one long line, with the satellite in the
middle.  Pictorially:

     ----------O----------     as opposed to:

    |       |
    |       |
    |--O--|
    |       |
    |       |

  --Rob