Re: Slow Moving Object observed in (UK?)

Bjoern Gimle (b_gimle@algonet.se)
Mon, 29 Sep 1997 05:40:03 +0100

>>>1997 July 5 22h53mUT 18h06m DEC -8.5deg (2000?)
...
>>>stopped fading. From latest observations the observer predicts the
>>>following visibility:
>>>Sept 25 20 55 UT 0.2deg south of beta Aqr mag 9
...
>The observer did not quote coordinates and has no telephone for me to
>chase these details. However he is located in a small town called
>Freshwater on the west coast of the Isle of Wight, a sizeable island off
>the southern coast of England. Does this help?

Indeed it does. The position of Milstar (and most other geostationary
satellites at other times) agrees well within the +/-0.05 degree accuracy
of the report.

I used 50.6 N, 2.0 W, estimated from a map.

The time of the July observation is 3 minutes late, wrt. Rainer's elset,
and I don't have a later one. If your prediction for Sept.25 is correct,
it is about 23 minutes late (but OK in Decl.), and a corrected elset would be:

mod.Milstar 2                                    35839 x 35743 km
1 23712U 95 60  A 97145.00000000  .00000000  00000-0  00000+0 0    03
2 23712   2.9693 293.5913 0011385  21.1609 292.0014  1.00257700    05

This makes it 4 minutes EARLY on July 5, but it is an acceptable error
if we want to get reasonably correct predictions for late September.
(And if your Sept.25 prediction is correct, and the same satellite)
The non-linearity can be caused by perturbations, particularly orbit
adjustments. 




------------------------------------------------------------
-- b_gimle@algonet.se              +46-8-7428086  (home)  --
-- 59.22371 N, 18.22857 E, 44 m     AND member of :       --
-- http://www.algonet.se/~b_gimle   SeeSat-L              --
-- bjorn@tt-tech.se                +46-8-59095783 (office)--
------------------------------------------------------------