Ed's ASC 1 (85-76C, 15994) observation has at least three interesting properties - I suggest that observers concentrate on looking a half-cycle earlier, ie 03:05:27 UTC Nov.06 1. The 3:37 time is 2/3 cycles after the first series - not the usual 1/2-period phase shift. 2. This phase shift is found consistently in the series observed after the observation break. If it can be observed and timed with some magnitude information, determination of spin axis is facilitated. 2. Since the rotation period is much longer than Superbird A's, observations with UTC flash times from different parts of the USA should easily determine the rotation direction. (USA is about 6 degrees wide from the geos, so it must rotate about 3 degrees - if near-polar axis - so times would differ up to 4 seconds! 3. When a geo is observed 3:37 to 5:18, it moves 25 degrees relative to the stars. The Sun-Sat-Obs angle changes by 25 degrees, so the satellite may have to turn 12.5 degrees more (or less) to produce a flash. So in one day, the satellite will make 1/2 spin more (or less). (Actually, this is a standard synodic effect - since the period determined from these 13 cycles is actually 13.034 or 12.966 revolutions, and after 24 hours the geometry is almost identical to the first observation, so there must be an integer number of revolutions when using the ADJUSTED period) The third point is common to most geoflashers. > it again after I got to my apartment). As 7:44.50 * 186 equals > 86,397 seconds (3 seconds short of one day), it appears that it > will flash at almost the same times tonight, except perhaps > shifted in phase. It was still going strong when I called it > quits. > > 3:09:22 UTC Nov 5 (times rounded off) > 3:17:07 > 3:24:51 > 3:32:36 > 3:37:47 fractional time ... ----------------------------------------------------------------- Unsubscribe from SeeSat-L by sending a message with 'unsubscribe' in the SUBJECT to SeeSat-L-request@lists.satellite.eu.org http://www.satellite.eu.org/seesat/seesatindex.html
This archive was generated by hypermail 2b29 : Mon Nov 05 2001 - 10:51:08 EST