Hi Paul, Thank you very much for posting this video. I thought I'd take a try at identifying the 'darksat' in the crowd. I compared the video to positions computed by the current Celestrak TLEs. I got most of the satellites running about a second ahead, but I set your location as somewhere in Carefree, AZ; you could easily be one second's travel (about eight km) from the lat/lon I used. Also, the objects are presumably maneuvering, and I know from experience that fitting TLEs to moving targets is a pain. (Never tried it with low-flying ones on ion propulsion, though; a negative drag/BStar term might do the trick. But I digress.) After pattern-matching stars on the chart with those in the video, I found that the center of your FOV is at about 10h24m, dec -38 45'; FOV is about 1.5x1 degree. The stars visible at the start of the video are (you may need to set fixed-spacing fonts for this chart to make sense) ----------------------------------- | 2 3 | | 1 | | 6 | | 4 | | | | | | | | 78 | | 5 | | | | | ----------------------------------- 1 = mag 8.0, HD 90868 2 = mag 7.5, HD 90725, with a mag 9.4 just above it 3 = mag 7.0, HD 90335 4 = mag 8.4, HD 90256 5 = mag 9.0, HD 90017 6 = mag 9.5, HD 89951 7 = mag 9.3, PPM 742900 = TYC 7713 419 8 = mag 6.9, HD 90549 Note that star 6 is a class M, probably at least somewhat variable. I'd bet you don't normally get mag 9.5 stars that clearly. The pattern of passing Starlinks is mostly quite close to that you'd get from looking at the TLEs. I mostly just focussed on the ones around the dark satellite, and made the following identifications (i.e., Starlink 1113 was passing the center of the FOV at 13:25:41). 13:25:41 1113 13:25:43 1119 13:25:47 1114 13:25:50 1084 & 1130 (DARKSAT)? 13:25:53 1098 13:25:58 1123 13:26:01 1097 13:26:07 1099 13:26:10 1104 13:26:16 1144 13:26:24 1103 13:26:31 1101 The problem is that Darksat ought to have been between 1084 and 1098. Instead, you get a close pairing of satellites at the point where 1084 went by, and you don't see anything for Darksat. Everybody else is pretty much where it ought to be. I may be jumping to a conclusion here (always a popular form of exercise). But it seems to me that the 'double' at 13:25:50 in your video is 1084 and another satellite, and I think it's Darksat, and I don't think it's noticeably dark (the pair look identical). -- Bill _______________________________________________ Seesat-l mailing list http://mailman.satobs.org/mailman/listinfo/seesat-lReceived on Wed Jan 08 2020 - 19:26:20 UTC
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