Brad Young and Paul Sventek have reported positional observations. There is a problem getting Paul's messages to the list, so he reported his obs off-list: WGS84 observation position 35d 42.70N, 97d 39.78W gps elevation 1111' (just northwest of Oklahoma City, OK) time: 18 Feb 2008, 00:57:54.4 UT J2000.0 5h 37m 58s +21d 26' 28" (near zeta Tau) Here it is in IOD format: 29651 06 057A 9999 P 20080218005754400 17 15 0537580+212628 99 S In addition to the positional observations, I have made use of a couple of images. The first one was imaged on 2008 Feb 17, I estimate near 02:33:30 UTC, and is available here (registration may be required to access it): http://www.bautforum.com/astrophotography/70430-decaying-spy-satellite-usa-193-i ss-cross-heart-orion.html Note that the likely site coordinates of the above are shown in the message header. The second one was imaged by Oscar A. Rodriguez on 2008 Feb 17, I estimate near 19:00:10 UTC (site coordinates are on the image): http://satobs.org/seesat/Feb-2008/0310.html The images are not accurately timed; therefore, I could not include data from them in the differential-correction; however, they do provide a superbly accurate record of the path among the stars, so I used them as a sanity-check of the differential-correction. As a result, I am more confident in the shape and orientation of the orbit, which should reduce track errors, compared with my epoch 08048 elset. USA 193 5.0 2.5 0.0 4.3 v 250 X 257 km 1 29651U 06057A 08049.03290930 .00227439 00000-0 27958-3 0 02 2 29651 58.5131 39.7259 0005095 99.1484 261.0195 16.07330305 09 Arc 2008 Feb 11.46 - 18.04, WRMS residuals = 0.1 deg Predicted arrival times tonight are uncertain by at least 10 s; track uncertainty is 0.2 deg. Rate of altitude decrease is about 1.3 km/d (kilometres per day). Using the above elements and a 10.7 cm solar flux of 70, Satevo v0.51 estimates decay from orbit on 2008 March 15. The uncertainty is at least several days. Definition of 2-line elements format: http://spaceflight.nasa.gov/realdata/sightings/SSapplications/Post/JavaSSOP/SSOP _Help/tle_def.html Ted Molczan ------------------------------------------------------------------------- Subscribe/Unsubscribe info, Frequently Asked Questions, SeeSat-L archive: http://www.satobs.org/seesat/seesatindex.html
This archive was generated by hypermail 2b29 : Mon Feb 18 2008 - 15:02:35 UTC