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. ------------------------------------------------------------------------- Subscribe/Unsubscribe info, Frequently Asked Questions, SeeSat-L archive: http://www.satobs.org/seesat/seesatindex.html
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