Flaring Geosat Season -- reminder

From: Ed Cannon (ecannon@mail.utexas.edu)
Date: Wed Sep 04 2002 - 05:39:23 EDT

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    For all of you at latitude 60 south, your "flaring geosat 
    season" is *now*!  
    
    Here's a copy of my reminder of this topic from a year ago -- 
    but with the links updated:
    
    "This is a reminder that "Flaring Geosat Season" is approaching!  
    
    "For new folks, around the equinoxes operational geostationary 
    satellites can brighten to much brighter magnitudes than usual, 
    so that they can be much easier to observe.  Along with the 
    seasonality, the phenomenon is latitude-dependent as well.  
    Here's slightly adapted version of a table of suggested 
    optimum dates for various latitudes originally published by 
    Rainer Kresken:
    
    latitude    optimum date
    -80         01 September
    -60         04 September
    -40         09 September
    -20         15 September
    0           23 September
    +20         30 September
    +40         07 October
    +60         12 October
    +80         15 October
    
    "Rainer's original, very informative message on the topic is
    at this location:
    
     http://www.satobs.org/seesat/Sep-1999/0002.html
    
    "Last year about the end of September and into early October I 
    was able to see several of them for a number of consecutive 
    evenings using only my 10x50 binoculars.  What I learned was 
    to look at two or three easily recognizable asterisms at the 
    correct declination.  I use Highfly for geosat/near-geosynch
    satellite predictions.
    
    "One note I would add is that, apparently due to tolerances 
    allowed for pointing of solar panels, the constraints on when 
    the satellites can flare are somewhat flexible.  Ones that 
    are very accurately pointed at the Sun might flare according 
    to very strict time constraints just near shadow entry and 
    exit, but those that are more "off" from exact solar pointing 
    can flare earlier and/or later than they "should" if they were 
    more accurately pointed.  I found last year that I could see 
    them across quite a large expanse of the sky on each of the
    evenings.
    
    "A second note is that there are some operational ones that are 
    not at zero inclination, and I believe that they can flare a 
    somewhat different times due to that fact as well.
    
    "There's more information on this page of Jason Hatton's site 
    in the section called "Operational geosats":
    
     http://members.aol.com/_ht_a/hattonjasonp/hasohp//GEO.HTML#Operational
    
    "See also the paragraph about "beaming" on the VSOHP page about 
    geosats:
    
     http://www.satobs.org/geosats.html
    
    Unquote.  Note that these are operational geosats -- not to be
    confused with "flashing geosynchs", which are not operational.  
    
    Last March, Mike McCants found about 60 flaring geosats, roughly 
    one every five minutes during a marathon observing session -- 
    and I got a look at almost all of them, also. 
    
    With some good luck, in rare cases it's possible to see one 
    without magnification!
    
    Ed Cannon - ecannon@mail.utexas.edu - Austin, Texas, USA
    
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