Another ISS / Venus update

From: Thomas Fly (tfly@alumni.caltech.edu)
Date: Mon Jun 07 2004 - 14:10:20 EDT

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    I have GTOPO30 implemented (at least as far as generating the ISS/Venus transit
    track; subscriber reports will take a bit more work), so the currently posted
    text files giving the ground tracks reflect the elevations above the ellipsoid /
    geoid / Geoid / or something... In any case, the ones I've checked (up to about
    4000 meters, and down to -30 meters) are quite close to what CalSKY gives.
    
    I originally typed GOTO30 up there... too little sleep... must have had
    nightmares about programming in BASIC and FORTRAN  ;-)
    
    Hopefully, the MCC will update their ISS TLE page by at least 23:00 UTC (6 PM
    Central Daylight Time, Houston), in which case I'll generate new tracks & a
    bunch of zoomed-in maps.  If they don't, I'll fall back on OIG.
    
    
    Tuesday, there was a high elevation Jupiter encounter thru Charlotte, NC (~160
    miles round-trip).  The night before, I ran an OIG track, and it shifted by only
    about 100 meters from the MCC track, predicted over 7 days earlier.
    
    I was all set to make the trip, having downloaded aerial photographs into
    DeLorme Topo USA 5.0 (a REALLY COOL program!), when I plotted the
    hot-off-the-press MCC track... it was 1.5 miles to the NW of the previous
    predictions!
    
    The weather was iffy (but naturally turned out good), and I was out of time for
    doing another Topo USA analysis, so in frustration, I aborted.
    
    I don't have precise data, but a subscriber in Charlotte who was between the 2
    tracks indeed confirmed that the new MCC track was substantially right- and the
    OIG track from only about 20 hours before was substantially wrong!
    
    So if possible, I'll be placing my bet on MCC; caveat emptor, CalSKY believers
    ;-)
    
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