Have you thought to "umbra" and "penumbra"? See for example: http://www.astro.washington.edu/courses/labs/eratosthenes/caveat_umbra.html Add to this Sun ray diffraction by our athmosphere and ISS disappearence becomes gradual. Giuseppe -------------- next part -------------- An HTML attachment was scrubbed... URL: http://mailman.satobs.org/mailman/private/seesat-l/attachments/20110502/a275a070/attachment.html _______________________________________________ Seesat-l mailing list http://mailman.satobs.org/mailman/listinfo/seesat-l
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