# Re: UNKNOWN OBJECT

Bjorn Gimle (Bjorn_Gimle@lector.kth.se)
Sat, 22 Jul 95 00:05:58 +0100

```Alphonse Pouplier wrote :

> On April 10,1991, Gerhart Klaus had made 2 photographs at about 10 min.
> of interval. On each one, one can see a line made by "a moving
> object". What could it be?
> Here are the coordinates of that object:
>	    UT   RA 1950  DEC 1950
> A         2005 09h21.8m +24d18m
> B         2010 09h24.5m +24d23m
> C         2014 09h26.7m +24d27m
> D         2019 09h29.4m +24d31m
> One can deduct that the speed (on the stars) is 6.8 deg./hour
> Could it be a satellite at 65,180 Km height ?
> If necessary, I can ask him for the coordinates of his obs.place.

If the times are not more accurate than a minute, I don't think I
need to know more than the country (Switzerland?)

The height you suggest would give an almost circular orbit.
If an elliptical orbit is assumed, the range at the time of
observation could be up to about 90000 for the perigee (sic!)
(even more for a passing asteroid?), down to about 38000 at the
apogee of a low-perigee orbit, which is quit common for the transfer
stages of geostationary satellites.

For an elliptical orbit at the intermediate ranges, it is also
possible for the satellite to be approaching or receding at the time
of the observation, which is very hard to determnine unless the timing
precision matches the positional precision. This will give a wide range
of excentricities and inclinations.

I have computed a number of possible, approximate orbits, assuming the
satellite was observed near apogee (or perigee) :

60000 km Pouplier-Klaus
1 91000U 91-x     91101.41715728  .00000000  00000-0  10000-4 0    17
2 91000  26.9415  66.4842 0294091  91.8864 271.4895  0.49097584    13
50000 km Pouplier-Klaus
1 91001U 91-x     91101.52100000  .00000000  00000-0  10000-4 0    11
2 91001  27.2700  66.1529 3626272 256.9927  60.8552  1.04347501    10
40000 km Pouplier-Klaus
1 91002U 91-x     91101.69600000  .00000000  00000-0  10000-4 0    15
2 91002  27.7471  65.7206 6394730 258.0435  28.3688  1.84955077    19

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Bjorn_gimle@lector.kth.se == bjorn.gimle@duesenberg.se ==
== bjorn.gimle@online.dextel.se ;  59.22371 N, 18.22857 E
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