Greg Roberts has recovered an object that is believed to be USA 125. He will post his observations in the near future. An observer who prefers not to be identified provided an approximate search orbit based upon a very short arc: 1 71001U 02233.27083333 .00000000 00000-0 00000-0 0 01 2 71001 63.5900 202.0000 7143000 271.4000 116.5300 2.00630000 04 Greg took excellent advantage of his southern hemisphere location and his computer-controlled CCD camera to recover the object on 2002 Nov 06 UTC. Knowing that the predicted time would be unreliable, Greg programmed his camera to stare at the orbital plane for a long period of time around the predicted time of the pass. This requires that the pointing system compensate for Earth's rotation, to keep the orbital plane centred within the field of view. Greg found the object running about 68 min late relative to the 77 day old search elements, and he obtained 11 accurate points. Using those points I obtained the following orbit: 1 23945U 96038A 02310.86007639 .00000000 00000-0 00000-0 0 07 2 23945 63.6507 193.7140 6920287 271.4039 348.2961 2.00665000 09 WRMS error = 0.011 deg I manually set the mean motion, and allowed Elcor to adjust the other elements. I chose the mean motion that resulted in approximately the same ephemeris as the search elements on their epoch date. On 2002 Nov 09 UTC, Greg found the object trailing the above elements by about 8 s, and he obtained 7 more points. Using the 06 Nov and 09 Nov points, I obtained the following elements: USA 125 0.0 0.0 0.0 5.7 v 1 23945U 96038A 02313.88997685 .00000000 00000-0 00000-0 0 01 2 23945 63.6190 193.3656 6917012 271.2979 17.0173 2.00658750 08 WRMS error = 0.01 deg The standard magnitude is based on Greg's observations. Users of software that employs the SDP4 "deep space" model, please note that the above elements were fit to SGP4; therefore, accuracy will be somewhat degraded using SDP4, even though it is superior for this type of orbit. The discrepancy is small within the observational arc - 2 or 3 s of time. I do not know how that will propagate over time. Finally, the identification as USA 125 may change after further tracking / analysis. Ted Molczan ----------------------------------------------------------------- Unsubscribe from SeeSat-L by sending a message with 'unsubscribe' in the SUBJECT to SeeSat-L-request@lists.satellite.eu.org http://www.satellite.eu.org/seesat/seesatindex.html
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