Simultaneous Nadir Overpasses (SNOs) between NOAA-21 and FY3D
TLE Epoch: 2022 12 6.  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, -46.94) 12/08/2022   23:14:09  ( -81.20, -47.02)    1.38                67
 12/09/2022   00:06:02   (  81.21, 119.99) 12/09/2022   00:04:56  (  81.20, 119.98)    0.46                66
 12/09/2022   00:56:37   ( -81.21, -72.58) 12/09/2022   00:55:41  ( -81.20, -72.50)    1.38                56
 12/09/2022   01:47:22   (  81.21,  94.73) 12/09/2022   01:46:27  (  81.20,  94.89)    2.68                55
 12/09/2022   02:37:57   ( -81.20, -97.83) 12/09/2022   02:37:13  ( -81.20, -97.98)    2.52                44
 12/09/2022   03:28:42   (  81.20,  69.48) 12/09/2022   03:27:59  (  81.20,  69.41)    1.21                43
 12/09/2022   04:19:17   ( -81.20,-123.08) 12/09/2022   04:18:44  ( -81.20,-123.07)    0.20                33
 12/09/2022   05:10:02   (  81.20,  44.22) 12/09/2022   05:09:30  (  81.20,  44.32)    1.55                32
 12/09/2022   06:00:37   ( -81.20,-148.33) 12/09/2022   06:00:15  ( -81.20,-148.16)    2.91                22
 12/09/2022   06:51:22   (  81.20,  18.97) 12/09/2022   06:51:02  (  81.20,  18.83)    2.32                20
 12/09/2022   07:41:56   ( -81.20,-173.59) 12/09/2022   07:41:46  ( -81.20,-173.64)    1.03                10
 12/09/2022   08:32:41   (  81.20,  -6.28) 12/09/2022   08:32:32  (  81.20,  -6.26)    0.54                 9
 12/09/2022   09:23:17   ( -81.20, 160.78) 12/09/2022   09:23:18  ( -81.20, 160.88)    1.74                 1
 12/09/2022   10:14:02   (  81.21, -31.92) 12/09/2022   10:14:04  (  81.20, -31.74)    3.18                 2
 12/09/2022   11:04:37   ( -81.20, 135.53) 12/09/2022   11:04:50  ( -81.20, 135.40)    2.19                13
 12/09/2022   11:55:22   (  81.20, -57.18) 12/09/2022   11:55:36  (  81.20, -57.22)    0.76                14
 12/09/2022   12:45:57   ( -81.20, 110.27) 12/09/2022   12:46:21  ( -81.20, 110.31)    0.54                24
 12/09/2022   13:36:42   (  81.20, -82.43) 12/09/2022   13:37:07  (  81.20, -82.31)    2.06                25
 12/09/2022   14:27:17   ( -81.20,  85.02) 12/09/2022   14:27:52  ( -81.20,  85.21)    3.25                35
 12/09/2022   15:18:02   (  81.20,-107.69) 12/09/2022   15:18:39  (  81.20,-107.79)    1.81                37
 12/09/2022   16:08:37   ( -81.20,  59.77) 12/09/2022   16:09:24  ( -81.20,  59.73)    0.66                47
 12/09/2022   16:59:22   (  81.20,-132.94) 12/09/2022   17:00:10  (  81.20,-132.89)    0.97                48
 12/09/2022   17:49:58   ( -81.20,  34.13) 12/09/2022   17:50:56  ( -81.20,  34.25)    2.11                58
 12/09/2022   18:40:42   (  81.19,-158.20) 12/09/2022   18:41:42  (  81.20,-158.37)    2.92                60
 12/09/2022   19:31:17   ( -81.19,   9.26) 12/09/2022   19:32:27  ( -81.20,   9.16)    1.84                70