Now that we know that the 219 heading is magnetic (thank you, Scott) and some approximate fireball celestial positions (thank you, Marco), we can consider The magnetic declination was 14° 43.92' West: http://www.geomag.nrcan.gc.ca/calc/mdcal-r-en.php?date=2017-05-28&latitude=11.935&latitude_direction=1&longitude=33.2883 333000&longitude_direction=-1&grid=on Therefore, the true heading was 219 - 14.732 = 204 deg. According to the present ephemeris, which is based on the aircraft's position about 1 min. after the sighting, the ground distance to the fireball varied between about 160 km and 960 km. It was closest near the beginning of the sighting, which based on the reported duration of 2 min., would have been about 3 min. prior to the known position of the aircraft. Assuming ground speed of about 15 km/min., it moved about 45 km during that time. Its motion was roughly toward the fireball; therefore, it is worth taking into account the motion of the aircraft. Not surprisingly, the greatest difference between the fixed-position ephemeris I posted last night and the fireball positions estimated by Marco, occurs near the start of sighting. And the differences are not small. Can the ground speed be seen on the instrument display? If not an estimate based on the model of aircraft could be used to estimate its position throughout the sighting. Ted Molczan _______________________________________________ Seesat-l mailing list http://mailman.satobs.org/mailman/listinfo/seesat-lReceived on Mon May 29 2017 - 05:00:11 UTC
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