Op 25-5-2011 19:00, Ted Molczan schreef: > Bram, Marco, Ralf Vandebergh and Russell observed it on the same pass last night (May 24) between 23:21 and 23:24 UTC. > Marco reported that it initially flashed 1 to 3 times per second, but later in the pass it had a period of about 1.6 s: [...] > That is close to the 1.73 s that Bram reported. More exactly, in the later part of the pass (image 7, 23:23:42 - 23:23:52 UTC) the flares were on average separated by 1.57s +/- 0.19s. This value is highly influenced however by the first flash interval determination though which appears somewhat anomalous to the rest of the series. If I drop the first one (marked * below) in that series which might be somewhat spurious because it is very close to the image start, I get 1.65s +/- 0.09 which is close to Bram's 1.73s. image 7, 23:23:42.30 - 23:23:52.35 UTC (May 24) delta T between flashes (s): 1.19 * 1.68 1.62 1.63 1.51 1.79 From the earlier part of the pass (image 4, 23:22:22 - 23:22:32 UTC), I get an average flash separation time of 0.57s +/- 0.15s (see below). However, the flash rate was clearly variable over that time span. In fact, determined flash intervals appear to be all multitudes of ~0.3s, with most near ~0.6s but a few ~0.3s (marked < ) and one ~0.9s (marked +): image 4 23:22:22.30 - 23:22:32.35 UTC (May 24) delta T between flashes (s): 0.66 0.33 < 0.61 0.67 0.37 < 0.63 0.61 0.33 < 0.63 0.67 0.94 + 0.62 0.38 < 0.58 0.62 0.50 0.52 Also note that Bram's 1.73s is very close to a multitude 3 of my 0.57s (0.57s x 3 = 1.71s) from this earlier part of the pass. As a note: I did not manage to observe Nanosail last night, cirrus here in Leiden was too thick, alas. - Marco (who has still obs from USA 161 and USA 224 from Tuesday night to reduce) ----- Dr Marco Langbroek - SatTrackCam Leiden, the Netherlands. e-mail: sattrackcam@wanadoo.nl Cospar 4353 (Leiden): 52.15412 N, 4.49081 E (WGS84), +0 m ASL Cospar 4354 (De Wilck): 52.11685 N, 4.56016 E (WGS84), -2 m ASL SatTrackCam: http://home.wanadoo.nl/marco.langbroek/satcam.html Station (b)log: http://sattrackcam.blogspot.com ----- _______________________________________________ Seesat-l mailing list http://mailman.satobs.org/mailman/listinfo/seesat-l
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