Superbird A's Flash Period Changed (?)

Jim Varney (sat_watcher@rocketmail.com)
Wed, 3 Sep 1997 21:59:05 -0700 (PDT)

The "usual" 11.3 second and 12.0 second half-periods reported by Mike
McCants and Ed Cannon for Superbird A is a behavior that *mostly* did
not exist in October 1996.  In October I made 295 flash period timings
of Superbird with the following distribution of timings:

<= 11.5 sec  7.1 percent
11.6 to 11.8 sec  85.8 percent
>=11.9 sec  7.1 percent

Statistical summary of the 295 observations:

Mean  11.6970 sec
Standard Error	0.00744
Standard Deviation  0.12780

Interestingly, the few 11.3 sec periods that do show up among the 295
are all followed by 12.0 sec timings.  There is some significance to
this because this pattern is not likely caused by a timing error. 
Timing errors happen when the observer has an inconsistent reaction
time when a flash is seen.  If I hesitate for a split second on a
timing, it would cause the first period to be long and the second
period to be short.  The only way for observer error to cause a
short-long pattern is for the observer to hit the stopwatch *before*
the flash is seen.

In October Seesatters concluded that the true period of Superbird was
23.4 seconds, not 11.7.  But this was based on perceived differences
in brightness of the flashes -- bright, dim, bright -- and not on an
unbalanced half-period.  This was most evident during the "ramp-up"
and "ramp-down" before and after a flashing session.  The "dim" flash
would disappear, leaving a true 23.4 sec period.

Anyway, I think it would be worthwhile to continue to make detailed
observations of Superbird A to see if anything can be learned from
these subtle aspects of its behavior.

__________________________________________________
Jim Varney   121.398W  38.458N 8m   Sacramento, CA
jamesv@softcom.net, sat_watcher@rocketmail.com

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