new WorldView source released

From: Thomas Fly (tfly@alumni.caltech.edu)
Date: Sat Dec 11 2004 - 12:25:47 EST

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    It may be downloaded at:
    https://sourceforge.net/projects/iss-transit/
    
    If you click on the email icon, under the column Notes/Monitor, you'll automatically receive an email notice when future 
    releases are posted.
    
    Additional information is here:
    http://iss-transit.sourceforge.net/alert-notes.html
    
    The principal enhancement to this version was in adding support for the SRTM-30 global elevation data set; however, 
    WorldView is also apparently unique in accounting for atmospheric ray-bending.  At 37 elevation (above the horizon), 
    atmospheric ray-bending in effect adds about 7 meters to the observer's MSL elevation; while near the horizon, it adds 
    about 2 kilometers in effective elevation.
    
    As a specific example, an ISS solar transit I have for this afternoon (naturally, it's mostly cloudy today!), at about 
    22 elevation, is predicted to pass .008 above the sun's center by CalSKY, corresponding to a shift of the ground track 
    by about 1/3 km.
    
    Someone recently tried to modify WorldView for his personal use, to create ground tracks for other low-earth orbit 
    satellites, but as far as I know he didn't succeed.  One modification that's necessary (I'll probably get around to it 
    eventually, though I'm not sure when) is to read the observer location(s) from a text file, rather than an Oracle 
    database.
    
    I doubt the value of trying to observe transits of satellites much smaller than the Shuttle, but one potentially useful 
    feature of such a modification would be to change the ground track tick-mark resolution from 1 to 0.1 seconds, giving a 
    resolution with respect to distance that's about the same as SRTM-30.  To represent 30'-resolution elevations within a 
    200x200 mile area would require less than 1/4 MB of disk space.
    
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