Hi All, Got some real good timing data on TDF-1 (#19621) last night. This satellite is definitely slowing down. In two days the period has increased from 29.666 +/- .006 to 29.804 +/- .002, an increase of .07 seconds per day. This compares favorably with Rick Baldridge's period measurement on August 17 (UT) of 29.24 seconds: Aug 17 29.24 Aug 23 29.666 + .426/6 = .071 Aug 25 29.804 + .138/2 = .069 So by Aug 28, the period will be just over 30 seconds, increasing by a little over 2 seconds per month. Incidentally, the center of last night's (Aug 24; Aug 25 UT) peak for my location in southern California was about 6:06 UT, 5 minutes later than what I had predicted. So my spin axis still needs some work. The pointing normals I have so far span less than 2 degrees (with a fair amount of uncertainty on those points), so the 5-minute error is not surprising. Only more data points (preferably from geographically separated regions) will improve the model. PPAS report for TDF-1 (19621, 88098A): 88- 98A 99-08-25 06:13 RM 730.20 0.05 24.5 29.804 mag +2 -> inv