Re: Slow moveing unknown

Philip Chien (kc4yer@amsat.org)
Tue, 11 May 1999 12:02:04 -0400

Stephmon@aol.com said:

>First, the best match for time and path (the star plot shows it actually
>passing -through- the bowl of the big dipper). Alldat doesn't include a mean
>magnitude, but a mag 0 pass would require an extremely fortunate 'flare'
>geometry, or a mean magnitude of roughly +0.7 (I think we would all be
>familiar with it, if this were the case). Is anyone familiar with this object?
>
>UTC		Sat Name	Sat #	Elev.	Azimuth	Height
>02:25:05	90081CD	20971	 20°	161° [S]	 830
>02:28:55	90081CD	20971	 81°	073° [E]	 827
>02:32:45	90081CD	20971	 20°	350° [N]	 824


1990 81A was a Chinese weather satellite.  CD would imply that some kind of
orbital breakup occurred, probably with the booster's final stage - but I'm
just guessing (could have been the satellite).  So it's highly doubtful
that any of the pieces are large enough to produce bright flares.


>The next two pass through the handle, very near the bowl (between delta and
>epsilon Ursa Major). Calculated magnitudes are 4.8 for Iridium 59 and 5.4 for
>DMSP B4D2-7. Iridium 59 should have been far from a favorable flare geometry,
>but if it has strayed from its ideal antenna orientation, a flare might be
>possible.
>
>UTC		Sat Name	Sat #	Elev.	Azimuth	Height
>02:26:35	Iridium 59	25275	 20°	175° [S]	 775
>02:30:15	Iridium 59	25275	 79°	087° [E]	 775
>02:33:56	Iridium 59	25275	 20°	006° [N]	 775

Based on what's been posted I would bet on Iridium 59 being the best
candidate, even though it wasn't predicted to flare at that particular
moment.



Philip Chien, KC4YER
Earth News
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