Hallo Alain, Your mail triggered me to take another look at the 2015 images I made of 31702. In the images with flashes or flares I selected a small part in the middle of the flare/flash. The images are 250 frames stacked in a 10 sec image, but the time of each frame is known. Below is a table with 2015 month and day and the measured period in seconds between two flares/flashes. Twice the same date indicates also images in the next pass. 01-02 almost steady 01-04 almost steady 02-15 10.154; 10.160 02-18 4.964 from secondary fl to main fl 02-19 10.12 02-22 9.971; 5.137 from secondary fl to main fl 02-22 10.439; 10.205; 10.420 02-25 10.362 02-28 10.263 02-28 10.956; 10.301 03-03 10.348; 10.378 03-04 10.373; 10.324 03-05 10.362; 10.402; 10.335 03-08 10.465; 10.444 03-11 10.482 03-12 9.621; 10.580 03-13 10.302; 10.275; 10.416 03-13 10.620 03-17 10.620 03-18 10.820 03-18 10.509 03-19 single fl 03-22 10.860 03-23 single fl A lot of variations and not a clear trend. But that can be caused by the longer flares where it was more difficult to get close to the exact middle. When time permits Iĺl have a look at the 2014 images of 31702. Regards Leo 2015-03-23 18:35 GMT+01:00 Alain Figer via Seesat-l <seesat-l_at_satobs.org>: > On 22 March 2015 I measured the rotation period of this rocket (2007-027B , # 31702 ) at 10.54 seconds, from 36 (4-second) photos. > > According to the PPAS, the period was measured in summer 2007 as long as 80-90 seconds, and shortened ever since, see for example : > > https://www.flickr.com/groups/1983844_at_N22/discuss/72157634322261108/72157651456081766 > > Does somebody know the why of this persistent period shortening ? (fuel leakages ?) > > > > Regards > > Alain Figer > > 48.67 N ; 2.13 E ; 170 m a.s.l. > _______________________________________________ > Seesat-l mailing list > http://mailman.satobs.org/mailman/listinfo/seesat-l _______________________________________________ Seesat-l mailing list http://mailman.satobs.org/mailman/listinfo/seesat-lReceived on Tue Mar 24 2015 - 09:56:22 UTC
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