The diagram shows in sequence, 7 orbital tracks of the ISS. The pattern shows the 51 degree inclination with Earth's equator, also the westward shift in the track caused by the rotation of Earth between each 90 minute orbit. The oval, with Avonport marked in the middle, represents the point at which the Space Station would rise above (generally from the westward) or drop below the Avonport horizon (to the eastward). 6 of the 7 orbits pass through the Avonport sky. Visible passes would only be those that have the observer in Earth shadow while ISS is in sunlight.

 

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