Observations 06 Jul 2005: ------------------------------- 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 145mm focal length f/2.5 lens. I normally integrate for 96 frames for geostationary objects which is equivalent to an exposure of 1.92 seconds per image. Successive images are then stacked on top of one another 200 times, giving an effective total exposure of 200*1.92 seconds = 384 seconds. Stars show up as trailed objects whilst geostationary satellites appear as dots if the inclination is close to 0 degrees or else as slightly trailed objects, the length of the trail depending on the inclination and altitude. Site 0433 : Longitude 18.51294 deg East, Latitude 33.94058 deg S, Elevation 10 metres - situated in Pinelands (Cape Town), South Africa For CLASSFD.TLE: ------------------------ 27168 02 001A 0433 G 20050706193641300 56 15 1443480+031841 39 +095 05 27712 03 012B 0433 G 20050706193641300 56 15 1443473+031352 39 +095 05 27938 03 041B 0433 G 20050706192911400 56 15 1744443+084244 39 +090 05 90013 03 564A 0433 G 20050706193020800 56 15 1739346-021303 39 +075 05 90016 03 766A 0433 G 20050706173628500 56 15 1339345+041050 39 +105 05 90031 05 546A 0433 G 20050706181346800 56 15 1814149+044424 39 +125 05 90034 05 592A 0433 G 20050706193338800 56 15 1630272+040014 39 +110 05 90035 05 625A 0433 G 20050706192422400 56 15 1844302+051359 39 +090 05 90036 05 629A 0433 G 20050706181224500 56 15 1824391+032440 39 +125 05 90037 05 638A 0433 G 20050706185901900 56 15 1901542-082854 39 +090 05 90038 05 638B 0433 G 20050706182949300 56 15 1838550+023401 39 +110 05 Stray geostationaries measured: ------------------------------------- RADUGA 2 09416 76 092A 0433 G 20050706190755000 56 15 1846310-102431 39 +100 05 GORIZONT 2 11440 79 062A 0433 G 20050706190755000 56 15 1853056-103924 39 +105 05 INTELSAT 904 27380 02 007A 0433 G 20050706192422400 56 15 1845216+051446 39 +095 05 Stray LEO objects measured : ---------------------------------- COSMOS 1275 Debri (rocket?) 12654 81 053J 0433 G 20050706163754100 56 15 0945407-345001 39 SL-12 R/B(2) 15334 84 106B 0433 G 20050706162824700 56 15 1034355-401855 39 +060 05 ROCSAT 1 25616 99 002A 0433 G 20050706172252700 56 15 0822572-183646 39 +030 05 Notes: ------ (1) First hour or so was spent carrying out an orbital plane scan. Although I still have to go through the DVD recording slowly nothing unknown was seen. (2) COSMOS 1275 rocket produced a spectacular flashing display - for those who like looking at flashing satellites this one is worthwhile watching. (3) MILSTAR 6 CNr is now passing MILSTAR 5 - they were close together and about equal in magnitude. (4) #90035 and Intelsat 904 still continue their dancing together but tonight was the maximum distance I have seen them apart. (5) I made a boo-boo after I completed the orbital plane scan when I changed the integration time for images from 48 ( which I use for LEO satellites ) to 128 frames instead of my usual 96 frames. Whilst the images appeared okay on the monitor in "real-time" mode they turned out very "washed out"- ie low contrast when frames (exposures) were added (stacked) together the next day. It would seem that with 128 frame integration the background sky noise level becomes too high and reduces the signal to noise ratio of the satellite to the background sky. It would thereafore appear that I should get better results using short exposures and stacking of numerous frames rather than using long exposures with fewer frames. Guess its similar to the chemistry question - is it better to do one or too large washings of a precipitate or numerous small washings - ( I know the answer - I was a chemist several decades ago before becoming a professional astronomer). Cheers Greg ------------------------------------------------------------------------- Subscribe/Unsubscribe info, Frequently Asked Questions, SeeSat-L archive: http://www.satobs.org/seesat/seesatindex.html
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