After the Season 6 Finale we also see that the orbs and rings we see in the opening are most likely an astrolabe (aka armillary sphere, armilla, or armil).
We see the same object hanging in the Citadel at Oldtown. This can be determined by seeing the same markings on the rings.
The meaning of this is still not fully known, but there is an interesting fan theory...
"The overarching saga is called A Song Of Ice And Fire after all, and in the world of Game of Thrones songs are used to pass on heroic stories and legends. So does that mean somebody is telling this story of Dany, Jon, Arya, Cersei, and the rest to future generations?"
"If that’s how it ends, some fans might be mad about the set up of the story. But if this theory is right, does it make sense for Sam to be the one that devotes his life to passing along the heroism and cruelty of everyone in Westeros? Or could it be Sam’s son who was told the story by his father and then passes it on to his own children? If this theory is accurate, there are any number of options that would make sense. But for now it is just another theory."
As for the "blinking effect" the fan theory is that this is literally a person blinking because that person is using the optical device we see the Maester at Oldtown using.
Answer originally posted on M&TV