**Previous message:**Sheldon Cooper: "Skycube"**In reply to:**Kevin Fetter: "Re: Now where's the champain = I see the unid sat :)"**Messages sorted by:**[ date ] [ thread ] [ subject ] [ author ]

Hi Kevin, Mike, all, After adapting some of my software I am now able to do brute force parameter searches to find the best fitting orbital elements. The software creates a grid of mean motion and eccentricity values and for each pair it fits the remaining parameters and stores the rms of the fit. If the observations cover enough of the orbit there will be a minimum some where in the plane spanned by mean motion and eccentricity, which is where the elements fit the observations best. The software was used on Kevin's slow unknowns from April 4 (object 99300), July 6 (object 99208) and July 13 (object 99209). For the latter there is a clear minimum around a mean motion of 4.1 revs/day and eccentricity near 0.6. In the case of 99208 the observational arc is short so the minimum is very broad, but it shows that for a given pair of mean motion and eccentricity the fits give similar values for inclination, argument of perigee, RA of ascending node and mean anomaly to the fits to object 99209. This confirms that the observations of July 6 and 13 belong to the same object. This is the best fit orbit, which has very small residuals (0.02 deg rms). 1 99208U 13594A 13190.79412873 .00000000 00000-0 00000-0 0 08 2 99208 20.1181 285.3465 5983547 150.2423 150.9703 4.12069308 02 This is an approximate search orbit, and with a perigee of 223 km the Bstar drag term might be quite large; expect the object to be early or late. Furthermore, the parameter searches show that the object of April 4 (object 99300) is not the same; here the best fit parameters suggest a mean motion of 2.5 revs/day with an eccentricity near 0.7, combined with very different values of the other orbital parameters. I hope that this analysis proves useful in recovering object 99208. Regards, Cees -------------- next part -------------- An HTML attachment was scrubbed... URL: http://mailman.satobs.org/mailman/private/seesat-l/attachments/20130714/4d28c32b/attachment.html _______________________________________________ Seesat-l mailing list http://mailman.satobs.org/mailman/listinfo/seesat-l

**Next message:**Derek C Breit: "DCB Obs JUL 14th UT - USA129 - FIA Radar 2 - etc"**Previous message:**Sheldon Cooper: "Skycube"**In reply to:**Kevin Fetter: "Re: Now where's the champain = I see the unid sat :)"**Messages sorted by:**[ date ] [ thread ] [ subject ] [ author ]

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