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Observations 02 June 2007: ---------------------------- Cosatrak 1 (Computerised satellite Tracking System). MINTRON low light level CCD surveillance camera (0.005 lux typical in non integration mode) and 0.00005 lux in STARLIGHT mode with 128 frame integration. Used with 50mm focal length f/1.8 lens,integrating for 96 frames which is equivalent to an exposure of 1.92 seconds per image. Site 0433 : Longitude 18.51294 deg East, Latitude 33.94058 deg S, Elevation 10 metres - situated in Pinelands (Cape Town), South Africa OPS 9845 - DMSP mag 5.5 to invisible - variable 13736 82 118A 0433 F 20070602163519400 56 15 1044170+160906 39 +055 05 SL-14 R/B Mag +6.5 steady 12880 81 098B 0433 F 20070602164602900 56 15 1043380+163042 39 +065 05 OPS 8364 - DMSP mag 6.0 to invisible - variable 06787 73 054A 0433 F 20070602165201500 56 15 1048460+192406 39 +060 05 Cosmos 1707 mag 4.0 steady 16326 85 113A 0433 F 20070602165535100 56 15 1039260+160944 39 +040 05 SL-14 R/B mag 6.0 steady 19791 89 009G 0433 F 20070602165954200 56 15 1111240+151801 39 +060 05 SL-8 R/B mag 3.0 steady 25723 99 022C 0433 F 20070602171510100 56 15 1124430+161901 39 +030 05 Iridium 69 mag +5.0 variable 25319 98 026A 0433 F 20070602171542800 56 15 1059310+175940 39 +050 05 Thor Agena rocket mag 4.5 steady 01245 65 016J 0433 F 20070602172030400 56 15 1107480+182432 39 +045 05 Iridium 76 mag 6.0 steady 25432 98 048B 0433 F 20070602172038600 56 15 1129060+190041 39 +060 05 SJ-6D mag 3.5 steady 29506 06 046B 0433 F 20070602173313400 56 15 1130060+162208 39 +035 05 Argos mag 6.5 steady 25634 99 008A 0433 F 20070602174549700 56 15 0922440+093136 39 +065 05 Atlas 5 centaur mag 7.0 variable, range 8670 kms 28473 04 048B 0433 F 20070602175953100 56 15 0950500+162519 39 +070 05 Meteor 1-26 mag 6.0 steady 09481 76 102A 0433 F 20070602180442400 56 15 0948390+114024 39 +060 05 Delta 1 Rocket body mag 6.5 steady, range 3240 kms 14051 83 041B 0433 F 20070602181419700 56 15 0946190+112021 39 +065 05 SL-8 R/B mag 7.0 steady 18710 87 106B 0433 F 20070602181543000 56 15 1003200+132321 39 +070 05 Delta 2 R/B mag 6.5 steady, range 3250 kms 21965 92 027B 0433 F 20070602181737500 56 15 0954320+111940 39 +065 05 Delta 1 R/B mag 7.0 steady 10517 77 118B 0433 F 20070602185058200 56 15 1036080+134512 39 +070 05 Delta 2 R/B mag 6.5 steady, range 2620 kms. 24809 97 025B 0433 F 20070602185647600 56 15 1043170+164839 39 +065 05 Notes: -------- (1) Satellites observed whilst looking for unknowns - nothing particularly exciting about them. (2) Am now occupying my time with improving the determination of orbital elements of unknown satellites and have made some very good progress. Using the method of Gauss ( 3 times and three positions) I am now able to determine the parameters of most satellites to within a few percent of the actual value at the time of observation - ALL the parameters are very close to the actual values except for a few percent error in the orbital period - usually of the order of 3 - 5 minutes after one day but in some cases within 5 minutes after 5 days. This applies to LEO as well as MEO satellites eg 63 degree inclination, mean motion around 2 revs per day. The procedure generates 18 equations in 18 unknowns but using the Lagrange coefficients f and g, as well as using the Stumpff functions and state vectors etc and applying the conservation of angular momentum, some valid approximations can be made which gives an initial solution, then by a process of iteration one homes in on the correct values that fit the observations. Full details of the method used may be found in "Orbital Mechanics for Engineering Students" by Howard D.Curtis (2005) - an excellant book on ALL aspects of orbital mechanics with lots of problems and detailed solutions. Preliminary tests indicate that a minimum arc covering 2 - 3 minutes in time is necessary to get the right answer. Anything less will only provide the RA of Node and the inclination. For the approximations made in the computation it is not wise to use too long an arc and a maximum of 10 degrees of the satellites orbit is recommended in the literature. Further testing is being done but so far results are extremely encouraging - ( something I did NOT expect when I started as I did not consider it possible to derive an eccentric orbit from a very small arc of the satellites orbit!) Cheers Greg ------------------------------------------------------------------------- Subscribe/Unsubscribe info, Frequently Asked Questions, SeeSat-L archive: http://www.satobs.org/seesat/seesatindex.html

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