Obs 971028 + acceleration of 91-19 B

Leo Barhorst (leobarhorst@pi.net)
Tue, 28 Oct 1997 23:09:09 +0100 

91-19 B IS ACCELERATING !!!!
Last night and this evening I observed 91- 19 B and it is accelerating; 
looking at my latest observations of this sat it is very clear

91- 19 B 97-10-18 19:08:35   LB   72.3 0.5   1 72.3   AA, mag 3->inv
91- 19 B 97-10-20 18:20:22   LB   62.9 0.5   1 62.9   AA, mag 4->inv
91- 19 B 97-10-27 17:57:12   LB   89.9 0.5   4 22.5   AA, mag 4->inv
91- 19 B 97-10-28 18:25:24   LB  113.9 0.5   6 19.0   AA, mag 3->inv

The sat is an easy object and will be visible here for several more nights;
in the evening low in the west, in the morning with higher passes in the east.
More obs from other observers are needed as we can follow the acceleration
of this sat.
When we plot the graph of all 91-19 B obs in PPAS we see that this rocket
has had an acceleration already. About 1100 days after launch the period was
some 100+ seconds; the sat was not observed till day 1475 when it was flashing
at 2.5 seconds. At day 2000 (end 0f 1996) it was at 25 seconds; in jan 97 I
observed it at 34 seconds. Just 10 days ago it was 72 and two days later 63 sec.
It is now going down rapidly and we are lucky to be able to observe it as it will
probably reach it minimum period in just a few days.


This evening I also obseved the following sats:

70-108 A 97-10-28 18:06:39   LB   77.9 0.2   2 38.9   FF, mag 4->inv
79- 21 B 97-10-28 19:01      LB                       almost s, mag 4
80- 87 B 97-10-28 19:12:32   LB  192.1 0.2  24  8.00  Ff, mag 5(7)->inv
80- 98 B 97-10-28 17:55:33   LB   83.4 0.2   6 13.90  FF, mag 5->inv
86-100 B 97-10-28 19:01      LB                       almost S, mag 5
90- 23 B 97-10-28 19:04      LB                       almost S, mag 6
91- 19 B 97-10-28 18:25:24   LB  113.9 0.5   6 19.0   AA, mag 3->inv
92- 30 J 97-10-28 18:55:20   LB  112.7 0.5   4 28.2   AA, mag 4->inv
93- 55 C 97-10-28 19:08      LB                       S, mag 7

and these two Iridium obs:
NORAD  date      time  Dir aI eI aM  eM  aS  eS Phs Dur Mag  Obs COSPAR Ir
xxxxx yy-mm-dd hh:mm:ss x xxx xx xxx xx xxx -xx xxx  tt Sn.n III yynnnx xx
24869 97-10-28 18:00:36 S 161 52 127 56     -16      10  2   LB  97034A 15
24869 97-10-28 18:01:04 S 165 42  52 77     -16       5  1   LB  97034A 15
24872 97-10-28 18:17    S        317 69     -18         S6   LB  97034D 20
 

-- 
Greetings and clear skies
Leo Barhorst       Alkmaar    The Netherlands
52.65 North        4.47 East  3 m ASL
Every day I wonder about what I see in the sky