Re: Telstar 401

From: b_gimle@algonet.se
Date: Fri Nov 11 2005 - 04:30:34 EST

  • Next message: Greg Roberts: "Obs 09 Nov 2005 Part 2"

    >                                                                            
    >> "I was able to see much more of Telstar 401's flash 
    episode                
    >> earlier tonight, from about RA 23:50 to 00:15, 
    roughly.                    
    >> The brightest maxima may have been zero magnitude.  ...
    >                        
    > I'd like to try from up here in Tulsa tonight since it will be 
    clear.
    > I presume you expect flashes 6 min earlier tonight also?
    > Is there much of a correction due to 
    latitude?                                                
    >                                                                            
    > +36.1 
    -95.9                                                                
                         
    The points I have 2002-01-08 to 2004-02-28 all agree well,
    but Ed's new obs disagrees 3-4 degrees, mainly in declination.
    Since the path of the flash rotation and the satellite track
    are both roughly parallell to the declination circles, the
    prediction is very sensitive to changes.
    
    With a slight correction to match Ed's obs, I get his
    position predicted, and also a second event near RA 5:00.
    The back side (?) may also cause flashes at dusk near RA 19:30.
    If one of these can be found (or observations late 2004-early 
    2005 can be retrieved) I can make a much better prediction.
    
    With the current guestimate, Ed's event would have about
    the same daily change at nearby latitudes.
    
    The effect of +10E longitude is about RA +00:06, dec.+0.2, time +0:12
    +5(!)N is RA -00:16, dec. -0.7, time -0:17  
    
    My prediction results in a daily change of RA +00:04:30,
    but since the satellite is 0:04 earlier/day at a fixed RA,
    I get a net effect of +0:00:30 in time. Ed's -0:06 in time
    requires a change of -00:02 in RA, the flash path and track
    must intersect in the other direction, and my RA/dec changes
    for lat/long would get reversed signs, and half the size!  
    
    It would also mean that a larger change, than the 3-4 degree
    discrepancy suggests, is needed for the axis/cone angles,
    and requires more observations to revise the model :-( 
    Please give RA/dec and time to at least 00:01/0.2 00:01 accuracy.
    
    /Björn
    
    
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