Simultaneous Nadir Overpasses (SNOs) between NOAA-21 and FY3D
TLE Epoch: 2022 12 8.  Predictions up to the next  14.0 days:

     Date     Time(NOAA-21) NOAA-21 Lat/Lon Date Time(FY3D) FY3D Lat/Lon    Distance(km)  Time Diff(sec)
 12/08/2022   23:15:16   ( -81.20, -47.21) 12/08/2022   23:14:09  ( -81.20, -47.28)    1.25                67
 12/09/2022   00:06:01   (  81.20, 120.11) 12/09/2022   00:04:55  (  81.20, 120.11)    0.22                66
 12/09/2022   00:56:36   ( -81.20, -72.46) 12/09/2022   00:55:40  ( -81.20, -72.37)    1.48                56
 12/09/2022   01:47:21   (  81.20,  94.85) 12/09/2022   01:46:26  (  81.20,  95.02)    2.87                55
 12/09/2022   02:37:56   ( -81.20, -97.71) 12/09/2022   02:37:12  ( -81.20, -97.85)    2.40                44
 12/09/2022   03:28:41   (  81.20,  69.60) 12/09/2022   03:27:58  (  81.20,  69.54)    1.00                43
 12/09/2022   04:19:16   ( -81.20,-122.96) 12/09/2022   04:18:43  ( -81.20,-122.94)    0.44                33
 12/09/2022   05:10:01   (  81.20,  44.34) 12/09/2022   05:09:29  (  81.20,  44.45)    1.79                32
 12/09/2022   06:00:37   ( -81.21,-148.60) 12/09/2022   06:00:15  ( -81.20,-148.42)    3.02                22
 12/09/2022   06:51:21   (  81.20,  19.09) 12/09/2022   06:51:01  (  81.20,  18.97)    2.14                20
 12/09/2022   07:41:57   ( -81.20,-173.85) 12/09/2022   07:41:47  ( -81.20,-173.90)    0.93                10
 12/09/2022   08:32:42   (  81.20,  -6.55) 12/09/2022   08:32:33  (  81.20,  -6.51)    0.70                 9
 12/09/2022   09:23:17   ( -81.20, 160.90) 12/09/2022   09:23:18  ( -81.20, 161.01)    1.84                 1
 12/09/2022   10:14:02   (  81.20, -31.81) 12/09/2022   10:14:05  (  81.20, -32.00)    3.24                 3
 12/09/2022   11:04:37   ( -81.20, 135.64) 12/09/2022   11:04:50  ( -81.20, 135.53)    2.03                13
 12/09/2022   11:55:22   (  81.20, -57.06) 12/09/2022   11:55:36  (  81.20, -57.09)    0.47                14
 12/09/2022   12:45:57   ( -81.20, 110.39) 12/09/2022   12:46:21  ( -81.20, 110.43)    0.71                24
 12/09/2022   13:36:42   (  81.20, -82.32) 12/09/2022   13:37:07  (  81.20, -82.18)    2.30                25
 12/09/2022   14:27:17   ( -81.19,  85.14) 12/09/2022   14:27:53  ( -81.20,  84.95)    3.19                36
 12/09/2022   15:18:02   (  81.20,-107.57) 12/09/2022   15:18:39  (  81.20,-107.66)    1.58                37
 12/09/2022   16:08:37   ( -81.19,  59.89) 12/09/2022   16:09:24  ( -81.20,  59.86)    0.64                47
 12/09/2022   16:59:23   (  81.20,-133.21) 12/09/2022   17:00:11  (  81.20,-133.14)    1.25                48
 12/09/2022   17:49:58   ( -81.20,  34.25) 12/09/2022   17:50:56  ( -81.20,  34.38)    2.23                58
 12/09/2022   18:40:42   (  81.19,-158.08) 12/09/2022   18:41:42  (  81.20,-158.24)    2.70                60
 12/09/2022   19:31:18   ( -81.20,   9.00) 12/09/2022   19:32:28  ( -81.20,   8.90)    1.65                70