3 GEOs in one night

Matson, Robert (ROBERT.D.MATSON@cpmx.saic.com)
Thu, 24 Sep 1998 12:47:23 -0700

Hi All,

It was a nice clear night by the beach for the first time in a while,
with no moon to interfere, so I got some good measurements.
Saw Superbird A (#20040) flashing from about 3:12 to 3:18:30 UT
Sept. 24.  Period was measured at 23.133 +/- .011 seconds.
Brightest flashes were around magnitude 2.5.

Took me a little while to find 98001 (its running about 4 1/2 minutes
late relative to this elset):

PACGEO           6.0  0.0  0.0  5.5 d
1 98001U          98201.73894482  .00000200  00000-0  16686+0 0    04
2 98001   3.9000  58.4786 0001000  81.0331 278.9668  1.00265000    07

By tweaking the mean motion and drag a bit, I get a better match
with this:

PACGEO           6.0  0.0  0.0  5.5 d
1 98001U          98201.73894482  .00000180  00000-0  16686+0 0    04
2 98001   3.9000  58.4786 0001000  81.0331 278.9668  1.00261000    07

The above elset works with SGP, HANDE or SDP4.  Measured
period was 10.049 +/- .003 seconds.  From southern California it
was already flashing at 4:14 UT, and was visible until at least
4:17 -- not that different from what Mike McCants observed a few
days ago.  Warning to those who try to observe this one:  it is
not an easy binocular object.  Flashes occur on the quarter-cycle,
and vary from invisible (dimmer than 8.5) to at most +6.  A star
chart showing the track plus stars to magnitude 8 will probably
be needed for acquisition.

My third GEO was Gorizont 14 -- first time I've seen it.  Many
thanks to Mike for the heads-up on this one!  This is an EASY
binocular object with consistent 5th magnitude flashes every
87.3 seconds.  I observed it for over an hour, timing 45 flash
periods in 3929.4 seconds.  Period was 87.320 +/- .003 secs.
It was flashing from at least 4:40 UT to 5:50 UT Sept 24.  The
following elements were fine for acquisition in 8 x 56 binocs:

Gorizont 14      3.0  0.0  0.0  6.0 d
1 17969U 87040A   98252.16551003 -.00000180 +00000-0 +10000-3 0 06472
2 17969 009.8167 043.6343 0024374 302.4399 057.4241 00.97659187020803

Because of the slow rotation rate, the flashes have noticeable
duration -- perhaps half a second.

Separate detailed reports being sent to PPAS.

Cheers!  --Rob