Simultaneous Nadir Overpasses (SNOs) between GOES-17 and FY3D
TLE Epoch: 2021 9 21.  Predictions up to the next  14.0 days:

     Date     Time(GOES-17)   GOES-17 Lat/Lon  FY3D Lat/Lon    Distance(km)  Time Diff(sec)
 09/21/2021   10:41:12   (   0.03,-137.21) (  -0.48,-134.86)  266.95                80
 09/22/2021   23:00:08   (  -0.03,-137.20) (  -0.70,-140.07)  327.24                80
 09/23/2021   22:43:50   (  -0.03,-137.20) (   0.37,-135.48)  196.00                80
 09/25/2021   11:02:37   (   0.03,-137.20) (   0.83,-140.65)  393.54                80
 09/26/2021   10:46:19   (   0.03,-137.19) (  -0.24,-136.06)  129.17                80
 09/27/2021   23:05:14   (  -0.02,-137.17) (  -0.93,-141.27)  466.58                80
 09/28/2021   22:48:56   (  -0.02,-137.16) (   0.08,-136.67)   55.59                80
 10/01/2021   10:48:45   (   0.01,-137.14) (   0.05,-137.26)   13.77                80
 10/03/2021   22:51:23   (  -0.00,-137.09) (  -0.15,-137.88)   89.39                80
 10/04/2021   22:35:04   (  -0.00,-137.07) (   0.86,-133.28)  432.07                80