Superbird A obs, more (what else?)

Jim Varney (jvarney@mail2.quiknet.com)
Wed, 02 Oct 1996 23:50:59 -0700

Here are my observations for Sept 29 and Oct 3 in PPAS format:

89- 41 A 96-09-29 03:29:03.55JEV 386.0 0.1  33 11.697 FF, geosynch

89- 41 A 96-10-03 03:34:32.84JEV 362.6 0.1  31 11.697 FF, geosynch

Std error for both the 31 and 33 obs sets is just under 0.1 sec.

The 31 and 33 flashes are continuous runs where there was no missed
flash.  In both cases there are 23.4 sec flash periods just before and
after the continuous runs.  Per PPAS convention, the times shown
are ending times.

No, I don't think the .001 accuracy is real.  Just lucky they matched.

Rob Matson wrote:

>This Superbird rotation business is getting interesting.  

To say the least!  Your "sweep analysis" is thought-provoking.  Another
factor to think about is that the flashing has been going on for some
time now, and so is somewhat insensitive to the sun's declination.

>The angle from the sun to the satellite to southern California is 113
degrees at
>3:25 UTC, 112 degrees at 3:30 UTC.

Using the same vector methods as my previous post, I get for Sacramento

0327   113.69	obs-sat-sun angle, Oct 3 UT
0335   113.95	obs-sat-sun angle, Oct 3 UT

Conceptually it would seem that it should decrease, but Superbird has
a retrograde motion in the sky during this time period (azimuth falling
slightly).

>So Robert Sheaffer in northern CA and Ron Lee in CO should see their peak 
>flashes several minutes before I do in southern CA.  This is testable.

A quick look at your obs from last night and mine from tonight seems to
indicate a time differential, but quite a bit less than "several minutes."
Perhaps the rotation axis is skewed, somewhere between the plane of the
orbit and the earth's poles?

Robert Sheaffer wrote:

>So, in the future we can tell people: "look for flashes from Superbird A
>when its sun angle is 53.7 degrees"?

No -- the 53.7 degrees was the case for that particular day.  As you can
in the above, the angle is opening up.

Jay Respler wrote;

>Sure, that's great for westerners.  But how much longer do we east 
>coasters have to wait to see it?       :)

Where were ya?  It was in your western sky in August!  :)

 -- Jim

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Jim Varney       | 121^ 23' 54" W,  38^ 27' 28" N   |           Sacramento, CA
Member, SeeSat-L |           Elev. 31 ft.           |                         
Member, Sacramento Valley Astronomical Society      |jvarney@mail2.quiknet.com
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