Mike McCants wrote: > But if Spacecom was using SDP4 to generate >elsets for eccentric objects and if a 50 second discrepancy between >Spacecom elsets and the model in Highfly was to be expected, you >would think that I would have noticed this some time in the last >15 years. :-) The SDP4 algorithm is known to have certain flaws. It often works but sometimes it seems to give poor results. Taking the TLE's given by Greg Roberts and checking the satellite's position at the exact time of epoch I find only a small difference between SGP4 and SDP4 (amounting to 8 sec). Similar discrepancies at similar times of the day might be due to 12 or 24 hour resonances. So in this particular case SDP4 might be the better result after all. What interests me is this: Has anybody actually observed *Unknown 041206* and found out which prediction is correct? Gerhard HOLTKAMP Darmstadt, Germany ------------------------------------------------------------------------- Subscribe/Unsubscribe info, Frequently Asked Questions, SeeSat-L archive: http://www.satobs.org/seesat/seesatindex.html
This archive was generated by hypermail 2b29 : Wed Mar 22 2006 - 17:25:50 EST