Re: Spectacular Double-Geosat Flare...Again!

From: Björn Gimle (bg_26934@glocalnet.net)
Date: Tue Feb 28 2006 - 13:52:40 EST

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    Ron,
    
    I forgot to include a note that as Kevin (and others) have observed,
    flares can be seen many degrees (ie weeks) from predicted pos (time).
    
    Anyway, theoretical optimum at 40N today, with Sun at 22:46  -7.8 d
    you (they) will be close to the shadow circle of 9.29 deg radius,
    centered at 10:46 +(7.8-6.29=)1.51 decl. at midnight.
    
    Your (their) Clarke belt is at -6.29, but the shadow circle extends
    down to (1.51-9.29=) -7.78 degrees, so the flaring geos will enter
    shadow some degrees west of 10:46  -7.78 (exit a few deg E),
    but most will probably be flaring at these points.
    
    Early in the evening RA will be around 11:05, decl. around -7.3
    
    And you can probably see flares for another week or two.
    
    ----- Original Message ----- 
    
    > Bjorn,  I could not tell what these charts mean.  Is it too late
    > to observe these flares at 39 deg N?
    >
    >>The center of the geoflares is at the Sun's declination,
    >>so it currently moves north. But to have the operational
    >>geosats a degree further north, you must travel six degrees
    >>south on the Earth's surface.
    >>
    >>Also note that the center of the Earth's shadow is at
    >>the anti-solar right ascension at local midnight,
    >>but at the opposite declination of the Sun!
    >>It is offset by the observers latitude, and also by
    >>the time of night. It moves < -00:10/hour in R.A.
    >>
    >>Also note that some geos (including XM-1/2?) have
    >>booster reflectors (at 60 deg angles?) causing extra
    >>flares 3-4 hours before/after expected maximum.
    >>
    >>Sun at 22:46 Latitude: 0     0     0    40    40    40    60    60 
    >>60
    >>        -7.8 Time  20:00 23:00 24:00 20:00 23:00 24:00 20:00 23:00 
    >> 24:00
    >>
    >>Shadow radius:      9.36 10.13 10.19  9.02  9.73  9.79  8.65  9.31 
    >>9.36
    >>Declination offset: 0.00  0.00 
    >> 0.00 -5.80 -6.25 -6.29 -7.50 -8.06 -8.11
    >>RA offset:         00:32 00:10 00:00 00:23 00:07 00:00 00:14 00:04 
    >>00:00
    >>
    >>Declination:        7.80  7.80  7.80  2.00  1.55  1.51 
    >> 0.30 -0.26 -0.31
    >>RA:                11:18 10:56 10:46 11:09 10:53 10:46 11:00 10:50 
    >>10:46
    >>
    >>Excel file available on request.
    >>
    >>----- Original Message ----- ...
    >>>  Question: What do you believe the
    >>>geographic extent of the visibility of this event? And
    >>>which way does it move night after night - north or
    >>>south?
    >>
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