Ed Cannon and I watched this geosync for over 80 minutes last night. Ed saw the first flash about 1:50UT Dec. 15. The first timed flash was at 1:51:29.4UT. The last timed flash was at 3:09:23.8UT. I have chosen the most reliable times to get 4410.9 seconds divided by 50 cycles = 88.22 seconds. The brightest flashes were visible to Ed even though this site (Bee Caves Research Center) is not very dark. Here are the estimated magnitudes for each flash: (I have indented the fainter flashes.) Cycle Magnitude number --- ---- 0 5? 1 9 2 9 3 5 4 inv 5 inv 6 9 7 6, 6 8 4, 6 9 9 10 11? 11 8 12 distracted by crossing sat 13 3.5, 2.5 14 7 15 inv 16 4 17 7.5 18 6, 3 19 2 20 9 21 inv 22 8 23 4.5 24 4 25 5.5 26 2.5 27 7.5 28 8.5 29 6, 6 30 3 31 3 32 5 33 8.5 34 7.5 35 5 36 4.5 37 4.5 38 9 39 10 40 9 41 9.5 42 5 43 9.5 44 10 45 inv 46 10.5 47 5 48 10.5 49 10 50 inv 51 6 52 6 53 9.5 54 8.5 Certain cycles (7, 8, 13, 18, 29) gave "double" flashes. The first of each pair seemed to be "slower" and the second seemed to be "sharper" (faster). The first of each pair seemed to be "on time" with the 88.22 second period and the second seemed to be about 3/4 second later. The cycles that did not give double flashes seemed to be slower flashes compared to the second flash of each double flash. The time of maximum brightness would seem to be around cycle 30. The cycles 30 flash occurred about 02:34UT Dec 15. This is quite possibly 25 to 35 minutes later than the time of maximum brightness the previous night. Alternatively, the time of phase shift could be around cycle 24 and that would be 02:25UT. There seems to be a superimposed period about every 5 cycles. If there is no "phase shift", there might be 9 cycles of this superimposed period between cycles 3 and 51. But it appears to me that there is a "phase shift" taking place between cycles 23 and 32 and that would mean 9.5 cycles of this superimposed period from cycles 3 to 51 and that would give a superimposed period of very nearly 5 cycles. Fascinating. :-) Mike McCants Austin, Tx