Simultaneous Nadir Overpasses (SNOs) between GOES-15 and NPP
TLE Epoch: 2017 12 20.  Predictions up to the next  14.0 days:

     Date     Time(GOES-15)   GOES-15 Lat/Lon  NPP Lat/Lon    Distance(km)  Time Diff(sec)
 12/20/2017   22:18:12   (   0.02,-135.34) (   0.56,-133.05)  261.39                80
 12/22/2017   10:37:19   (  -0.04,-135.39) (   0.61,-138.32)  333.40                80
 12/23/2017   10:21:14   (  -0.03,-135.38) (  -0.39,-133.78)  181.93                80
 12/24/2017   22:40:29   (   0.04,-135.28) (  -0.81,-139.08)  432.86                80
 12/25/2017   22:24:23   (   0.04,-135.27) (   0.18,-134.54)   82.02                80
 12/28/2017   10:27:26   (  -0.04,-135.29) (  -0.06,-135.29)    2.40                80
 12/30/2017   22:27:56   (   0.04,-135.16) (  -0.13,-136.05)  101.31                80
 12/31/2017   22:11:51   (   0.03,-135.13) (   0.86,-131.52)  412.43                80
 01/02/2018   10:30:58   (  -0.04,-135.15) (   0.31,-136.79)  185.68                80